| 1. |
- Fahmy, Khalid, et al.
(författare)
-
Expression analysis of a family of developmentally-regulated cytosolic sulfotransferases (SULTs) in Drosophila.
- 2013
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 150:2-3, s. 44-48
-
Tidskriftsartikel (refereegranskat)abstract
- We have compared the amino acid sequence of all four cytosolic sulfotransferases (SULTs) in Drosophila and analyzed their spatial expression patterns during development. Three out of four SULTs show distinct expression activity during embryogenesis, while the 4th SULT shows expression only post-embryonically. st1, st3 and st4 are expressed in non-overlapping expression domains mainly confined to organs of the alimentary canal such as esophagus, malphigian tubules, hindgut, as well as in the tracheal system. All these organs are surrounded by the hemolymph suggesting that Drosophila SULTs exert their function in detoxification of substances upon influx from the hemolymph.
|
|
| 2. |
|
|
| 3. |
- Lind-Halldén, Christina, et al.
(författare)
-
Genetic variation in Arabidopsis suecica and its parental species A-arenosa and A-thaliana
- 2002
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 136:1, s. 45-50
-
Tidskriftsartikel (refereegranskat)abstract
- Random amplified polymorphic DNA (RAPD) markers were used to estimate the level of genetic variation in Swedish accessions of the allopolyploid Arabidopsis suecica and its parental species A. thaliana and A. arenosa. The results showed clear differences among the three species with respect to the level of variation. A. arenosa was highly variable, A. thaliana showed a moderate level of variation whereas A. suecica was much less variable than the two other species. An extended analysis covering 19 Swedish populations of A. suecica corroborated the low level of variation in this species, yet 16 unique phenotypes were observed. No isolation by distance was observed. When the genetic variation was partitioned among and within populations of A. suecica, the results showed that the majority of the variation (81 %) occurred among populations. This result is interpreted as a strong indication that A. suecica is autogamous in nature.
|
|
| 4. |
- Pelger, Susanne, et al.
(författare)
-
Evolution of hordein gene organization in three Hordeum species.
- 1993
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 119:3, s. 219-231
-
Tidskriftsartikel (refereegranskat)abstract
- The inheritance pattern of hordein, the seed storage protein in barley, has been studied in two wild Hordeum species, H. murinum and H. pusillum. Three different diploid populations of each species were crossed, and the F1 plants were self-pollinated. The seeds with an F2 genotype were studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Several differences could be observed in the banding patterns of the parental populations. The analysis of recombinant banding patterns showed that in H. murinum there are at least four segregating loci, of which two code for B- and two for C-hordein. All the loci are linked on the same chromosome. In H. pusillum at least six segregating loci were found, of which three code for B and three for C-hordein. Five of the loci are linked, while the sixth showed independent segregation. The organization of the hordein genes differs not only between these two species but also between them and the different forms of H. vulgare, as well as with other species belonging to the tribe Triticeae. Extensive rearrangements must obviously have taken place among the members of the hordein gene family since the divergence of the species in the Hordeum genus. The possibility is discussed that the genes have been moved through transposition, a possible mechanism for the physical divergence of tandemly repeated sequences.
|
|
| 5. |
- Pelger, Susanne, et al.
(författare)
-
The reaction of monoclonal antibodies with hordeins from five different Hordeum species.
- 1989
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 111:3, s. 273-279
-
Tidskriftsartikel (refereegranskat)abstract
- Hordeins from H. vulgare, H. murinum, H. pusillum, H. bulbosum, and H. brevisubulatum were probed with five monoclonal antibodies raised against different hordein polypeptides from Hordeum vulgare cv. ‘Bomi’. The response pattern differed widely among species. One of the antibodies, CMpBChorl, was found to react with hordein from every tested species, and all of the antibodies reacted with at least one of the wild barley species. Antibodies reacting with many different hordein polypeptides in ‘Bomi’ showed a wide reaction also with other species, while more specific antibodies gave limited reactions outside of domesticated barley. In some cases hordein polypeptides reacting with a specific antibody differed in electrophoretic mobility between species, indicating that the hordein genes involved have undergone concerted evolution.
|
|
| 6. |
- Säll, Torbjörn, et al.
(författare)
-
Mode of reproduction in Arabidopsis suecica
- 2004
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 141:3, s. 313-317
-
Tidskriftsartikel (refereegranskat)abstract
- The breeding system of Arabidopsis suecica was investigated through genetic analysis of microsatellite segregation patterns in Five controlled crosses as well as in 16 single-mother families collected in the wild. Analysis of single and two-locus segregations in the F-2 generation following a cross clearly shows that A. suecica is reproduces sexually. The single-mother families show a high level of homozygosity corroborating earlier results indicating a high level of inbreeding. The high level of individual homozygosity is due both to a high level of selfing and to the underlying population structure.
|
|
| 7. |
- Troedsson, U, et al.
(författare)
-
Application of antisense transformation of a barley chitinase in studies of arbuscule formation by a mycorrhizal fungus
- 2005
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 142:1, s. 65-72
-
Tidskriftsartikel (refereegranskat)abstract
- Barley (Hordeum vulgare L.) plants of two commercial cultivars were transformed with sense and antisense constructs of a chitinase class II gene in order to develop a transformation system for this gene in barley. Transformation of embryos with the two antisense constructs resulted in ten regenerated plants, while no plants could be obtained using the sense construct. The presence of the inserted construct could be confirmed for six of the plants by PCR analysis. This system was used to study the role of class II chitinase in the regulation of mycorrhizal symbiosis. The colonization of two of the antisense transformants by the arbuscular mycorrhizal fungus Glomus intraradices was investigated microscopically and by use of signature fatty acids. The arbuscular incidence increased in transformed barley, and one transformant supported higher extraradical mycelium biomass. It is concluded that antisense transformation of barley could be a useful tool in investigations on the symbiosis between barley and mycorrhizal fungi.
|
|
| 8. |
- Bensch, Staffan, et al.
(författare)
-
Partial albinism in a semi-isolated population of great reed warblers
- 2000
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 133:2, s. 167-170
-
Tidskriftsartikel (refereegranskat)abstract
- Albinism in birds is thought to result from the expression of recessive alleles that disrupt melanin pigmentation at feather development. We have studied great reed warblers Acrocephalus arundinaceus in a recently founded and increasing population in Sweden during 15 years for the presence of birds with albinistic feathers. The study population was founded in 1978 and the few cases of albinism was exclusively recorded during the first five pears of our study (1985-1989). This fits to the expected pattern if albinism is governed by recessive alleles; we have previously demonstrated that the population suffered from inbreeding during the first years of our study. The albinistic birds experienced a similar lifetime reproductive success as normally coloured birds.
|
|
| 9. |
- von Schantz, Torbjörn, et al.
(författare)
-
Mate choice, male condition-dependent ornamentation and MHC in the pheasant
- 1997
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 127:2, s. 133-140
-
Tidskriftsartikel (refereegranskat)abstract
- The Hamilton and Zuk model predicts that genes for resistance to various pathogens may be continuously heritable due to selection disequilibria caused by coadaptional cycles of hosts and pathogens. The model further suggests that the expression of male secondary ornaments is condition-dependent and that only individuals with superior genetic disease resistance and vigour can fully express exaggerated secondary ornaments. Female choice is therefore expected to discriminate among males on the basis of secondary sexual characters in order to pass on genes for disease resistance that improve fitness in the offspring. In wild ring-necked pheasants, Phasianus colchicus, of the Revinge area in southern Sweden, females prefer to mate with long-spurred males and data on reproductive success indicate that they may improve their chicks' survival rate by doing so. Male spur length is positively correlated with age, body size and viability. MHC genotyping for both class I and class II B of pheasant males trapped in the study area identified eight MHC haplotypes and a total of 17 different MHC genotypes. Multivariate analyses revealed that MHC genotype is significantly associated with variation in both male spur length and male viability. These data indicate that polymorphic genes with a central role in immune recognition can be associated with viability and the expression of a condition-dependent intersexually selected male trait, thus supporting essential parts of the Hamilton and Zuk model.
|
|
| 10. |
- Andersson, Stefan, et al.
(författare)
-
Inbreeding depression in a rare plant, Scabiosa canescens (Dipsacaceae)
- 2002
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 136:3, s. 207-211
-
Tidskriftsartikel (refereegranskat)abstract
- Plants from a population of Scabiosa canescens, a locally rare species with a narrow ecological amplitude, were raised under uniform growth conditions to examine the phenotypic effects of one generation selfing and outcrossing. Particular attention was given to direct components of fitness (seedling biomass, rosette leaf number, head number, flower number per head), but two morphological characters (plant height, flower size) were also considered. Estimates of inbreeding depression (delta), adjusted for maternal effects and lack of balance, were compared and tested for significance using randomization and bootstrap procedures. Inbreeding significantly depressed several characters during both early and late stages of the life cycle, with delta ranging from 0.14 (flower size) to 0.37 (seedling biomass). Based on these and other results, we propose that S. canescens is susceptible to inbreeding and that the genetic basis of inbreeding depression varies across life stages.
|
|
| 11. |
- Arnason, Ulfur
(författare)
-
50 years after - examination of some circumstances around the establishment of the correct chromosome number of man
- 2006
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 143:1, s. 202-211
-
Tidskriftsartikel (refereegranskat)abstract
- Three authors, Levan (1975, 1978), Tjio (1978) and Hulten (2002)have independently described the establishment of the correct chromosome number of man Tjio and Levan 1956 and the background to that study. However, the three authors provide strikingly different accounts of this historical discovery. In this study I have examined the consistency between these accounts and details provided by the logbook kept at Cancer Chromosome Laboratory, University of Lund. For complementary details I have also consulted several persons that were active at the Institute of Genetics, Univ. of Lund, at the time of the discovery. Levan's (1975)Levan's (1978)accounts are both written in a modest way compared to the more self-centered narratives of Tjio and Hulten. His accounts are also consistent with all details that can be collected from the logbook. However, and most unfortunately, Levan is not explicit with respect to the dates of what might be different cytogenetic observations related to the determination of the correct chromosome number of man. The logbook leaves no room for various temporal details given by Tjio, which, if correct, might substantiate his account. Also Tjio's introduction of an alter ego into the narrative is apt to lessen the general credibility of his account. Tjio's (1978)contention of having made his human chromosome preparations at 2 a.m. on December 22nd or 23rd would be consistent with his claim that he arrived from Spain in early December 1955. His account of this crucial issue is incorrect, however, as he did not arrive at the Cancer Chromosome Laboratory until December 19. Hulten's claim of involvement becomes highly questionable in the light of her fading recollections of both the localities at the Institute of Genetics and the persons working there. Her temporal account, like that of Tjio, remains unsupported by the logbook. Examination of the logbook for temporal details relating to the establishment of the correct chromosome number of man suggests that Levan made his first preliminary 2n=46 human chromosome counts around December 20th - 23rd, 1955, and that Tjio made his first conclusive preparations two-three weeks after his arrival from Spain, that is in early January 1956.
|
|
| 12. |
- Dzhambazov, Balik, et al.
(författare)
-
Karyotypic analysis of two algae species Scenedesmus incrassatulus Bohl and Scenedesmus antennatus Bréb (Chlorophyta, Chlorococcales).
- 2003
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 139:1, s. 35-40
-
Tidskriftsartikel (refereegranskat)abstract
- The karyotypes (number, morphology and size of the chromosomes) of two algae species of Scenedesmus genus, S. incrassatulus and S. antennatus, were studied. The karyotype of S. incrassatulus (n=4) was asymmetric, characterized by two large metacentric, one large submetacentric and one small metacentric chromosomes. The karyotype assembly of S. antennatus (n=6) reveals two metacentrics and four submetacentrics. This karyotype was symmetric. The general chromosomal formulae of both species, as well as the total average metaphase length of their haploid set are presented. The results of chromosomal studies of other related species are compared and discussed. Data from the karyotypic analysis showed that S. incrassatulus, S. antennatus and S. obliquus are separate biological species from taxonomical point of view.
|
|
| 13. |
- Ek, M., et al.
(författare)
-
Microsatellite markers for powdery mildew resistance in pea (Pisum sativum L.)
- 2005
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 142, s. 86-91
-
Tidskriftsartikel (refereegranskat)abstract
- Powdery mildew is a common disease of field pea, Pisum sativum L., and is caused by the ascomycete fungus Erysiphe pisi. It can cause severe damage in areas where pea is cultivated. Today breeders want to develop new pea lines that are resistant to the disease. To make the breeding process more efficient, it is desirable to find genetic markers for use in a marker-assisted selection (MAS) strategy. In this study, microsatellites (SSR) were used to find markers linked to powdery mildew resistance. The resistant pea cultivar '955180' and the susceptible pea cultivar 'Majoret' were crossed and F-2 plants were screened with SSR markers, using bulked segregant analysis. A total of 315 SSR markers were screened out of which five showed linkage to the powdery mildew resistance gene. No single marker was considered optimal for inclusion in a MAS program. Instead, two of the markers can be used in combination, which would result in only 1.6% incorrectly identified plants. Thus SSR markers can be successfully used in marker-assisted selection for powdery mildew resistance breeding in pea.
|
|
| 14. |
|
|
| 15. |
- Beskow, Anna, et al.
(författare)
-
Susceptibility locus for epidermodysplasia verruciformis not linked to cervical cancer in situ
- 2001
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 135:1, s. 61-63
-
Tidskriftsartikel (refereegranskat)abstract
- Cervical cancer is strongly associated with infection by oncogenic forms of human papillomavirus (HPV), mainly HPV 16 and HPV 18. The aim of this study was to test if a locus previously mapped to a region on chromosome 17 qter in patients with epidermodysplasia verucciformis (EV) and psoriasis and considered to be responsible for an increased susceptibility to HPV 5, also is linked to increased HPV susceptibility in cervical cancer in situ. We also wanted to test whether HPV 16 positivity cluster in families with cervical cancer. DNA was extracted from formalin fixed biopsies of 224 affected from 77 families diagnosed with cervical cancer in situ. Two microsatellite markers (D17S939 and D17S802) containing the locus were genotyped and linkage analysis was performed. No linkage was found to any of the two markers, neither when considering all cancer cases as affected nor when only considering HPV 16 infected cancer cases as affected in the analysis. We conclude that the susceptibility locus for HPV 5 infections associated with EV and psoriasis does not seem to affect susceptibility to HPV 16, frequently detected in cervical cancer. Also, positivity for HPV 16 did not show a significant clustering in families.
|
|
| 16. |
- Brown, Keith S., Jr., et al.
(författare)
-
Chromosomal evolution in the South American Riodinidae (Lepidoptera Papilionoidea)
- 2012
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 149:4, s. 128-138
-
Tidskriftsartikel (refereegranskat)abstract
- We give the haploid chromosome numbers of 173 species or subspecies of Riodinidae as well as of 17 species or subspecies of neotropical Lycaenidae for comparison. The chromosome numbers of riodinids have thus far been very poorly known. We find that their range of variation extends from n =?9 to n =?110 but numbers above n =?31 are rare. While lepidopterans in general have stable chromosome numbers, or variation is limited at most a subfamily or genus, the entire family Riodinidae shows variation within genera, tribes and subfamilies with no single modal number. In particular, a stepwise pattern with chromosome numbers that are about even multiples is seen in several unrelated genera. We propose that this variation is attributable to the small population sizes, fragmented populations with little migration, and the behavior of these butterflies. Small and isolated riodinid populations would allow for inbreeding to take place. Newly arisen chromosomal variants could become fixed and contribute to reproductive isolation and speciation. In contrast to the riodinids, the neotropical Lycaenidae (Theclinae and Polyommatinae) conform to the modal n =?24 that characterizes the family.
|
|
| 17. |
- Dida, Mulatu Geleta, et al.
(författare)
-
Genetic diversity in sorghum (Sorghum bicolor (L.) Moench) accessions of Zambia as revealed by simple sequence repeats (SSR)
- 2011
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 148, s. 52-62
-
Tidskriftsartikel (refereegranskat)abstract
- Twenty seven accessions of sorghum conserved in the national gene bank of Zambia, representing two of the three agroecological regions of the country, were investigated using simple sequence repeats (SSR) markers in order to determine the extent and distribution of its genetic diversity. We used 10 microsatellite primer-pairs, which generated 2-9 alleles per locus and a total of 44 alleles across the 27 accessions. The observed heterozygosity (Ho(P)) among the accessions ranged from 0 to 0.19 with an average of 0.04 whereas the average expected heterozygosity (He(P)) among accessions was 0.07 in line with the fact that sorghum is predominately inbreeder. The analysis of molecular variance (AMOVA) revealed that 82% of the total genetic variation was attributable to the genetic variation among accessions (F(ST) = 0.824; p < 0.001) whereas the genetic variation within accessions accounted for 18% of the total genetic variation. AMOVA on sorghum accessions grouped based on four ethnic groups (Soli, Chikunda, Lozi and Tonga) associated with collection sites revealed a highly significant variation among groups (23%; p < 0.001). Although cluster analysis grouped most accessions according to their sites of collection, some accessions that originated from the same site were placed under different clusters. In addition to the extent and pattern of genetic diversity, consideration should also be given to other factors such as ecogeographic and ethnic differences when sampling sorghum genetic resources for rational and efficient conservation and utilization in the breeding program.
|
|
| 18. |
- Dida, Mulatu Geleta, et al.
(författare)
-
Inter simple sequence repeat (ISSR) based analysis of genetic diversity of Lobelia rhynchopetalum (Campanulaceae)
- 2009
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 146, s. 122-130
-
Tidskriftsartikel (refereegranskat)abstract
- An understanding of the patterns of genetic variation within and among populations of plant species is essential for devising optimum genetic management strategies for their conservation. Here, the inter simple sequence repeat (ISSR) technique was used to study genetic variation of the Afroalpine giant lobelia, Lobelia rhynchopetalum, based on ten populations sampled from Bale and Simen mountains in Ethiopia. The percentage of polymorphic loci across all samples (P(S)) and within population (Pp) was 78% and 27%, respectively. Regardless of a high total genetic variation, the species has quite low variation within populations. All genetic variation analyses revealed higher variation among populations than within populations (G'(ST) = 0.59, G(ST) = 0.63, F(ST) = 0.58). Analysis of molecular variance (AMOVA) that employed 156 ISSR markers revealed significant variations among populations; among the two mountain systems and among the three altitudinal groups (P < 0.001). The implications of these findings are discussed, especially from conservation point of view.
|
|
| 19. |
- Einarsdottir, Elisabet, et al.
(författare)
-
The genetic population structure of northern Sweden and its implications for mapping genetic diseases.
- 2007
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 144:5, s. 171-180
-
Tidskriftsartikel (refereegranskat)abstract
- The northern Swedish population has a history of admixture of three ethnic groups and a dramatic population growth from a relatively small founder population. This has resulted in founder effects that together with unique resources for genealogical analyses provide excellent conditions for genetic mapping of monogenic diseases. Several recent examples of successful mapping of genetic factors underlying susceptibility to complex diseases have suggested that the population of northern Sweden may also be an important tool for efficient mapping of more complex phenotypes. A potential factor contributing to these effects may be population sub-isolates within the large river valleys, constituting a central geographic characteristic of this region. We here provide evidence that marriage patterns as well as the distribution of gene frequencies in a set of marker loci are compatible with this notion. The possible implications of this population structure on linkage- and association based strategies for identifying genes contributing risk to complex diseases are discussed.
|
|
| 20. |
- Gullberg, Annika, et al.
(författare)
-
DNA fingerprinting reveals multiple paternity in families of Great and Blue Tits (Parus major and P. caeruleus)
- 1992
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 117:2, s. 103-108
-
Tidskriftsartikel (refereegranskat)abstract
- Paternity of nestlings in the great tit (Parus major) and blue tit (Parus caeruleus) was studied using DNA fingerprinting. Multiple paternity was found in five out of ten great tit families and two out of seven blue tit families. Among the great and blue tit families 7 out of 47 (15 %) and 3 out of 51 (6 %) of the nestlings, respectively, were the result of extra-pair matings. Thus, extra-pair fertilization was proven not only in the blue tit but also in the great tit, a species regarded to be strictly monogamous. In no case was the whole brood sired by an extra-pair male and no case of intraspecific brood parasitism was detected.
|
|
| 21. |
- Johansson, Åsa, et al.
(författare)
-
Identification of local selective sweeps in human populations since the exodus from Africa
- 2008
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 145:3, s. 126-137
-
Tidskriftsartikel (refereegranskat)abstract
- Selection on the human genome has been studied using comparative genomics and SNP architecture in the lineage leading to modern humans. In connection with the African exodus and colonization of other continents, human populations have adapted to a range of different environmental conditions. Using a new method that jointly analyses haplotype block length and allele frequency variation (F-ST) within and between populations, we have identified chromosomal regions that are candidates for having been affected by local selection. Based on 1.6 million SNPs typed in 71 individuals of African American, European American and Han Chinese descent, we have identified a number of genes and non- coding regions that are candidates for having been subjected to local positive selection during the last 100 000 years. Among these genes are those involved in skin pigmentation (SLC24A5) and diet adaptation (LCT). The list of genes implicated in these local selective sweeps overlap partly with those implicated in other studies of human populations using other methods, but show little overlap with those postulated to have been under selection in the 5 - 7 myr since the divergence of the ancestors of human and chimpanzee. Our analysis provides focal points in the genome for detailed studies of evolutionary events that have shaped human populations as they explored different regions of the world.
|
|
| 22. |
- Jonsson, Magnus, et al.
(författare)
-
Genetic divergence of climatically marginal populations of Vicia pisiformis on the Scandinavian Peninsula
- 2008
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 145:1, s. 1-8
-
Tidskriftsartikel (refereegranskat)abstract
- Vicia pisiformis L. is a perennial leguminous plant with a main distribution in broadleaved forest-steppes of eastern Europe. The species is classified as endangered (EN) according to the IUCN red-lists in both Norway and Sweden, due to severe fragmentation, small population sizes and continuing population decline. The populations on the Scandinavian Peninsula constitute the northern limit of the species distribution and are mostly restricted to warm stony slopes with predominantly southern aspects. In this study we used the AFLP method, which is a high-resolution genetic fingerprint method. Samples were collected from 22 Scandinavian populations. The overall genetic structure was analysed in an AMOVA, in a Mantel test and through constrained correspondence analysis (CCA). The ordination scores representing non-geographic genetic divergence were extracted from the CCA and analysed in a linear model using habitat variables and population size as explanatory variables. We found (i) a strong geographic structure, (ii) significant genetic divergence between populations, (iii) that this genetic divergence remained significant even after removing the effect of geography in a partial CCA and (iv) that the remaining non-geographic part of genetic divergence (distance from the ordination centre) was associated with aspect, populations with a northern aspect were more genetically divergent. Aspect explains more variation than population size and is the only variable retained in the minimal adequate model. We suggest that local adaptation has caused this divergence from an expected geographical pattern of genetic variation. This explanation is further supported by the association between aspect and specific AFLP fragments. Many plant populations are relics of a different climate (Aguirre-Planter et al. 2000; Despres et al. 2002; Pico and Riba 2002). In response to long-term climate change, populations can either migrate towards a more favourable climate or adapt to the new conditions (delaVega 1996; Jump et al. 2006). Species with limited dispersal ability are at risk of reaching isolated dead-ends of decreasingly suitable habitat, without any suitable habitat within dispersal distance (Colas et al. 1997). Isolated populations have to use their inherent evolutionary potential and adapt to changes in environmental conditions, or they will go extinct. As population fragments go extinct, those that remain will become increasingly isolated from each other both spatially and also genetically as the level of gene flow declines with increasing distance. Such correlation between genetic dissimilarities and geographic distances, known as isolation by distance (Slatkin 1993; Wright 1943), when found, suggests a history of geographically limited gene flow (Kimura and Weiss 1964). On top of an isolation by distance pattern there might be other genetic structures to be found. Occasional long-distance dispersal events for example may disturb geographic patterns with puzzling allele distributions as a result (Nichols and Hewitt 1994). Genetic drift is a process that will affect any pattern of genetic variation in a random fashion. Local adaptation through natural selection is a process that, if sufficiently strong in comparison with gene flow and genetic drift, will create patterns where genetic differentiation is associated with certain environmental conditions (Wright 1951). Several studies have shown the importance of local adaptation of populations (reviewed by Kawecki and Ebert 2004) (see also Bonin et al. 2006; Knight and Miller 2004; Kolseth and Lönn 2005; Lönn et al. 1998). Local adaptation can be strong also at small spatial scales (Snaydon and Davies 1976; Lönn 1993) even though it is sometimes very limited in terms of the number of genes involved (Kärkkainen et al. 2004) Environmental variability provides a base for biological variation by imposing differentiated selection pressures resulting in local adaptation. Topography provides large environmental variation within a relatively small area and thereby provides a basis for small-scale local adaptations. Depending on the local topographic possibilities populations can either migrate up and down slopes or along the same altitude to a different aspect to find a suitable microclimate. The dispersal distance will be much shorter per degree of temperature change during altitudinal migration (Hewitt 1996), than during simple latitudinal migration across a flat landscape. Slope and aspect are two important topographic parameters that determine the influx level of solar radiation, especially towards the poles where the total global radiation decreases (Larcher 2003). Vicia pisiformis is an endangered poorly-dispersed long-lived forest herb with its main distribution across the semi-open broadleaved forest steppes of eastern Europe. The Scandinavian populations are believed to be climate relict populations from warmer times. Earlier genetic studies of V. pisiformis using allozymes, RAPD:s and morhology, have found low to very low levels of genetic variation (Gustafsson and Gustafsson 1994; Black-Samuelsson et al. 1997; Black-Samuelsson and Lascoux 1999). Therefore we used AFLP (amplified fragment length polymorphism) markers, which detect even very small genetic differences between individuals. AFLP mainly analyse neutral variation, as the major fraction of most genomes is assumed to be neutral. However, since the AFLP-fragments are distributed randomly throughout the whole genome some fragments may be situated so close to regions under selection that they become more or less linked to them. This linkage disequilibrium between molecular markers and regions under selection, often referred to as quantitative trait loci (QTL), forms the basis for both QTL-mapping and marker assisted selection (MAS), reviewed by Dekkers and Hospital (2002). Gardner and Latta (2006) for example, found QTL under selection in both natural environments and in the greenhouse. Markers have been found to be connected to biomass production (Cavagnaro et al. 2006) and environmental variation (Bonin et al. 2006; Jump et al. 2006; Porcher et al. 2006). In this study we examine 22 Swedish and Norwegian populations of Vicia pisiformis and ask (i) if there is genetic differentiation between these populations, (ii) if there is can it be explained in its entirety by geographic location or (iii) can it partly be explained by habitat characteristics, suggesting local adaptation, or population size, suggesting genetic drift. We show that populations are differentiated geographically and that genetic variation in addition to the geographical pattern is associated with habitat.
|
|
| 23. |
- Kato, Rei, et al.
(författare)
-
Chromosome breakage induced in vivo by a carcinogenic hydrocarbon in bone marrow cells of the Chinese hamster
- 1969
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 61:1-2, s. 1-8
-
Tidskriftsartikel (refereegranskat)abstract
- THE morphology, incidence and distribution of chromosome breakage induced by 7,12-dimethylbenz (a) anthracene (DMBA) in a Chinese hamster cell line in vitro were studied recently by KATO (1968). The present work - a corresponding study of the immediate effects of DMBA on Chinese hamster cells in vivo - was undertaken as the first step in an investigation of the chromosomes of primary tumors induced by DMBA in the Chinese hamster.
|
|
| 24. |
|
|
| 25. |
- Lundmark, Magnus, et al.
(författare)
-
Asexuality alone does not explain the success of clonal forms in insects with geographical parthenogenesis
- 2006
-
Ingår i: Hereditas. - Oxford : Blackwell. - 0018-0661 .- 1601-5223. ; 143:2006, s. 23-32
-
Tidskriftsartikel (refereegranskat)abstract
- Asexual forms of invertebrates are relatively common. They are often more successful than their sexual progenitors. Especially in insects, the pattern called geographical parthenogenesis shows that asexuality is important in speciation and ecological adaptation. In geographical parthenogenesis the clones have a wider distribution than the sexual forms they originate from. This indicates that they have a broader niche they may utilize successfully. The cause of this apparent success is, however, hard to come by as the term asexuality covers separate phenomena that are hard to disentangle from the mode of reproduction itself. Asexual insects are often polyploid, of hybrid origin, or both and these phenomena have been argued to explain the distribution patterns better than clonality. In this study we survey the literature on arthropods with geographical parthenogenesis in an attempt to clarify what evidence there is for the different phenomena explaining the success of the clonal forms. We focus on the few species where knowledge of distribution of different ploidy levels allows for a distinction of contributions from different phenomena to be made. Our survey support that asexuality is not the only factor underlying the success of all asexuals. Evidence about the importance of a hybrid origin of the clones is found to be meagre as the origin of clones is unknown in the majority of cases. Asexuality, hybridity and polyploidy are intertwined phenomena that each and all may contribute to the success of clonal taxa. Polyploidy, however, emerges as the most parsimonious factor explaining the success of these asexual invertebrate taxa.
|
|
| 26. |
- Mujaju, Claid, et al.
(författare)
-
Genetic diversity in watermelon (Citrullus lanatus) landraces from Zimbabwe revealed by RAPD and SSR markers
- 2010
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 147, s. 142-153
-
Tidskriftsartikel (refereegranskat)abstract
- Low polymorphism in cultivated watermelon has been reported in previous studies, based mainly on US Plant Introductions and watermelon cultivars, most of which were linked to breeding programmes associated with disease resistance. Since germplasm sampled in a putative centre of origin in southern Africa may harbour considerably higher variability, DNA marker-based diversity was estimated among 81 seedlings from eight accessions of watermelon collected in Zimbabwe; five accessions of cow-melons (Citrullus lanatus var. citroides) and three of sweet watermelons (C. lanatus var. lanatus). Two molecular marker methods were used, random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) also known as microsatellite DNA. Ten RAPD primers produced 138 markers of which 122 were polymorphic. Nine SSR primer pairs detected a total of 43 alleles with an average of 4.8 alleles per locus. The polymorphic information content (PIC) ranged from 0.47 to 0.77 for the RAPD primers and from 0.39 to 0.97 for the SSR loci. Similarity matrices obtained with SSR and RAPD, respectively, were highly correlated but only RAPD was able to provide each sample with an individual-specific DNA profile. Dendrograms and multidimensional scaling (MDS) produced two major clusters; one with the five cow-melon accessions and the other with the three sweet watermelon accessions. One of the most variable cow-melon accessions took an intermediate position in the MDS analysis, indicating the occurrence of gene flow between the two subspecies. Analysis of molecular variation (AMOVA) attributed most of the variability to within-accessions, and contrary to previous reports, sweet watermelon accessions apparently contain diversity of the same magnitude as the cow-melons.
|
|
| 27. |
- Pham, Toan Duc, et al.
(författare)
-
Comparative analysis of genetic diversity of sesame (Sesamum indicum L.) from Vietnam and Cambodia using agro-morphological and molecular markers
- 2011
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 148, s. 28-35
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to comparatively analyze the genetic diversity of sesame (Sesamum indicum L.) using agro-morphological and molecular markers. Twelve sesame populations collected from three regions in Cambodia and Vietnam were used in this study. A high genetic variation was revealed both by agro-morphological and RAPD markers within and among the 12 sesame populations. The range of agro-morphological trait based average taxonomic distance among populations (0.02 to 0.47) was wider than that of RAPD based genetic distance (0.06 to 0.27). The mean distance revealed by agro-morphological markers (0.23) and RAPD markers (0.22) was similar. RAPD based analysis revealed a relatively higher genetic diversity in populations from South Vietnam as compared to the other two regions. Interestingly, populations from this region also had higher values for yield related traits such as number of capsules per plant, number of seeds per capsule, and seed yield per plant suggesting positive correlation between the extent of genetic variation within population and yield related traits in sesame. A highly significant positive correlation (r = 0.88, P < 0.001) was found between agro-morphological and RAPD markers in estimating the genetic distance between populations. Both methods suggested the existence of a substantial amount of genetic diversity both in the Vietnamese and Cambodian populations. Although both agro-morphological and RAPD markers were found to be useful in genetic diversity analysis in sesame, their combined use would give superior results.
|
|
| 28. |
- Rasmuson, Marianne
(författare)
-
Genealogy and gene trees
- 2008
-
Ingår i: Hereditas. - Oxford : Blackwell Publishing. - 0018-0661 .- 1601-5223. ; 145:1, s. 20-27
-
Tidskriftsartikel (refereegranskat)abstract
- Heredity can be followed in persons or in genes. Persons can be identified only a few generations back, but simplified models indicate that universal ancestors to all now living persons have occurred in the past. Genetic variability can be characterized as variants of DNA sequences. Data are available only from living persons, but from the pattern of variation gene trees can be inferred by means of coalescence models. The merging of lines backwards in time leads to a MRCA (most recent common ancestor). The time and place of living for this inferred person can give insights in human evolutionary history. Demographic processes are incorporated in the model, but since culture and customs are known to influence demography the models used ought to be tested against available genealogy. The Icelandic data base offers a possibility to do so and points to some discrepancies. Mitochondrial DNA and Y chromosome patterns give a rather consistent view of human evolutionary history during the latest 100 000 years but the earlier epochs of human evolution demand gene trees with longer branches. The results of such studies reveal as yet unsolved problems about the sources of our genome.
|
|
| 29. |
- Rasmuson, Marianne
(författare)
-
Old and new ideas about genes and behaviour.
- 2009
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 146:5, s. 198-203
-
Tidskriftsartikel (refereegranskat)abstract
- Genetic factors have long been recognized as contributors to variantion in behaviour both within the normal span and as mental diseases. The first attempts to make behaviour the subject of scientific genetic studies used likeness between twins and other relatives to confirm heredity. Later heritability has been used as a quantitative estimate of the genetic part of the variance. Attempts to localize genetic factors became possible when associations between phenotypic aberrations and karyotype were observed. Inborn errors of metabolism further confirmed that specific metabolic deficits could influence behaviour. Many kinds of common mental deficiencies such as senile dementia have a heterogeneous background, and so have normal variations in talents and personality. The mapping of the human genome, the availability of an unlimited number of genetic markers and efficient statistical tools promised ample discoveries of genes behind the variation. The expectations have not been fulfilled and more subtle influences on gene expression have to be assumed. Topics that are taken up include genomic imprinting, brain activation patterns, the importance of neurotransmitter regulation and non-additive interactions between genes and environment.
|
|
| 30. |
- Rasmuson, Marianne
(författare)
-
Trends in genetics - before the molecular era
- 2010
-
Ingår i: Hereditas. - : Wiley-Blackwell. - 0018-0661 .- 1601-5223. ; 147:5, s. 243-249
-
Tidskriftsartikel (refereegranskat)abstract
- Genetics grew into a scientific discipline during the first decade of the twentieth century, it prospered and became acknowledged in its first half, it widened into the molecular field during its second half. This expansion attracted scientists from nearby branches such as biochemistry, biophysics, cell biology, statistics and computer science, which started to call themselves geneticists without deeper insights into the classical genetics. They may be unaware of how far the science had advanced already before the molecular window was opened. Then, what is the essence of genetics? It is involved in all aspects of biology, and has branched into different disciplines, rather far apart. Still it is held together by its core, the evolutionary coalescence of all living organisms on earth and their surprisingly great conformity in physiological and hereditary mechanisms. In the early definitions before the year 1900 the word variation is often included, most bluntly as the science of variation. Similarities and differences between parent and offspring are also emphasised. Inheritance causes similarities but not complete likeness. The name of the subject, genetics, was introduced by W. Bateson in 1906 and defined as the scientific study of the heredity of individuals. Later definitions have become more extensive and include not only the transmission of the hereditary factors but also their nature and the way in which they influence the living organism at different stages and at different levels, from molecules to populations and ecosystems.
|
|
| 31. |
- Saisa, Marjatta, et al.
(författare)
-
Genetic differentiation among European whitefish ecotypes based on microsatellite data
- 2008
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 145:2, s. 69-83
-
Tidskriftsartikel (refereegranskat)abstract
- The amount of genetic differentiation at DNA microsatellite loci in European whitefish (Coregonus lavaretus) was assessed among ecotypes, populations and run-timing types. The magnitude of genetic changes potentially caused by hatchery broodstock rearing were also compared with those observed in corresponding natural populations. A total of 35 populations were studied, including 33 Coregonus lavaretus populations and two samples of Coregonus peled. Five of the six whitefish ecotypes in Finland were represented within C. lavaretus populations. Genetic diversity among C. lavaretus populations proved to be high compared to two C. peled populations. The genetic D-A distance between these two species was as high as 0.86. The genetic differentiation among ecotypes was generally low and thus gives support for the hypothesis of one native European whitefish species in Scandinavia. Among the ecotypes the northern, large sparsely-rakered, bottom-dwelling whitefish was most unique. Thus, observed genetic differences in quantitative traits have either developed independently of phylogenetic lineages, or have mixed and later changed according to environments and selection pressures. Overall genetic distances between the anadromous whitefish populations along the Finnish coast, especially in the Bothnian Bay area, were small. Populations of this area have been heavily influenced by human activities, and they also have the highest probability of mixing by natural means. In two cases, the Rivers Iijoki and Tornionjoki, statistically significant genetic differences could be observed between summer- and autumn-run spawning-time types. Wild populations had slightly higher allelic diversity than hatchery-reared populations of corresponding rivers. Although some reduction in genetic diversity during hatchery rearing is possible, it is an important aid in maintaining endangered populations.
|
|
| 32. |
- Saura, Anssi, et al.
(författare)
-
Chromosome evolution in Neotropical butterflies
- 2013
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 150:2-3, s. 26-37
-
Tidskriftsartikel (refereegranskat)abstract
- We list the chromosome numbers for 65 species of Neotropical Hesperiidae and 104 species or subspecies of Pieridae. In Hesperiidae the tribe Pyrrhopygini have a modal n = 28, Eudaminae and Pyrgini a modal n = 31, while Hesperiinae have n = around 29. Among Pieridae, Coliadinae have a strong modal n = 31 and among Pierinae Anthocharidini are almost fixed for n = 15 while Pierini vary with n = 26 as the most common chromosome number. Dismorphiinae show wide variation. We discuss these results in the context of chromosome numbers of over 1400 Neotropical butterfly species and subspecies derived from about 3000 populations published here and in earlier papers of a series. The overall results show that many Neotropical groups are characterized by karyotype instability with several derived modal numbers or none at all, while almost all taxa of Lepidoptera studied from the other parts of the world have one of n = 29-31 as modal numbers. Possibly chromosome number changes become fixed in the course of speciation driven by biotic interactions. Population subdivision and structuring facilitate karyotype change. Factors that stabilize chromosome numbers include hybridization among species sharing the same number, migration, sexual selection and possibly the distribution of chromosomes within the nucleus.
|
|
| 33. |
|
|
| 34. |
- Svensson, Malin J, et al.
(författare)
-
Thioredoxin-2 affects lifespan and oxidative stress in Drosophila
- 2007
-
Ingår i: Hereditas. - Oxford : Blackwell. - 0018-0661 .- 1601-5223. ; 144:1, s. 25-32
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Thioredoxins are proteins that have thiol-reducing activity and a characteristic conserved active site (WCGPC). They have several documented functions, e.g. roles in defences against oxidative stress and as electron donors for ribonucleotidereductase. In Drosophila melanogaster there are three ‘‘classical’’ thioredoxins with the conserved active site: deadhead, ThioredoxinT and Thioredoxin-2. Here, we report the creation of null-mutations in the Thioredoxin-2 (Trx-2) gene. Characterization of two Trx-2 mutants indicated that Trx-2 affects the lifespan of D. melanogaster, and is involved in the organism’s oxidative stress protection system. We found that the mutants have a shorter lifespan than wild-type flies, and thioredoxin double mutant flies showed lower tolerance to oxidative stress than wild-type flies, while flies carrying multiple copies of a Trx-2 rescue construct showed higher tolerance. These findings suggest that Trx-2 has modest or redundant functions in Drosophila physiology under unstressed conditions, but could be important during times of environmental stress.
|
|
| 35. |
- Säll, T., et al.
(författare)
-
Primer mixtures in RAPD analysis
- 2000
-
Ingår i: Hereditas. - 0018-0661 .- 1601-5223. ; 132:3, s. 203-208
-
Tidskriftsartikel (refereegranskat)abstract
- RAPD (random amplified polymorphic DNA) is a multiplex marker system that conventionally uses single-primer PCR to amplify random DNA fragments. Because of its multiplex nature, it is frequently used in bulked segregant analysis (BSA). In view of the very large numbers of markers BSA often requires, we investigated the use of mixtures of primers as a method of increasing the number of markers available. Theoretically, if a single-primer reaction produces x bands on average, an unrestrained PCR process using a primers should produce xa2 bands. Initially, we investigated mixtures containing from one to five primers. The average number of products increased slightly from the single-primer to the multiple-primer case, whereas it was rather constant for the different multi-primer combinations. This deviation from the theoretical expectations, which we attribute to the effects of competition, shows mixtures of more than two primers to be inefficient. The properties of two-primer mixtures in which the proportions of the two primers were varied were also investigated. The intensities of most of the products were influenced by the proportions of the primers used to create the mixture. A good fit was obtained to a model in which the average competitive ability of a band is directly proportional to the probability of randomly obtaining the band-producing primer combination from the pool of primers. Using two-primer mixtures, a(a-1)/2 different two-primer mixtures can be produced. A comparison of different schemes for constructing the two-primer mixtures indicates that the degree of resampling is similar for all schemes. In conclusion, the use of two-primer mixtures is a simple but very powerful strategy in BSA as it can generate an extremely large number of markers.
|
|
| 36. |
- Säll, T., et al.
(författare)
-
Primer mixtures in RAPD analysis
- 2000
-
Ingår i: Hereditas. - : BioMed Central Ltd.. - 0018-0661 .- 1601-5223. ; 132:3, s. 203-208
-
Tidskriftsartikel (refereegranskat)abstract
- RAPD (random amplified polymorphic DNA) is a multiplex marker system that conventionally uses single-primer PCR to amplify random DNA fragments. Because of its multiplex nature, it is frequently used in bulked segregant analysis (BSA). In view of the very large numbers of markers BSA often requires, we investigated the use of mixtures of primers as a method of increasing the number of markers available. Theoretically, if a single-primer reaction produces x bands on average, an unrestrained PCR process using a primers should produce xa2 bands. Initially, we investigated mixtures containing from one to five primers. The average number of products increased slightly from the single-primer to the multiple-primer case, whereas it was rather constant for the different multi-primer combinations. This deviation from the theoretical expectations, which we attribute to the effects of competition, shows mixtures of more than two primers to be inefficient. The properties of two-primer mixtures in which the proportions ofthe two primers were varied were also investigated. The intensities of most of the products were influenced by the proportions of the primers used to create the mixture. A good fit was obtained to a model in which the average competitive ability of a band is directly proportional to the probability of randomly obtaining the band-producing primer combination from the pool of primers. Using two-primer mixtures, a(a-1)/2 different two-primer mixtures can be produced. A comparison of different schemes for constructing the two-primer mixtures indicates that the degree of resampling is similar for all schemes. In conclusion, the use of two-primer mixtures is a simple but very powerful strategy in BSA as it can generate an extremely large number of markers.
|
|
| 37. |
|
|
| 38. |
- Von Bothmer, Roland
(författare)
-
Connection between rod bivalents and incomplete meiotic association at NORs in Hordeum marinum Huds.
- 2012
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 149, s. 139-145
-
Tidskriftsartikel (refereegranskat)abstract
- The hypothesis of a connection between rod bivalent formation and incomplete meiotic association at NORs of SAT-chromosomes of H. marinum is supported. PMCs of H. marinum ssp. gussoneanum (2x), two diploid ssp. marinum x ssp. gussoneanum (2x) hybrids and two ssp. gussoneanum (4x) x Secale cereale hybrids at metaphase I (M-I) were analyzed by in situ hybridization. The probe pTa71 labelled rDNA sites at NORs of a single pair of homologous or near-homologous SAT-chromosomes of H. marinum in each material. In the three diploids, M-I was regular with ring bivalents and one or a few rods (av.13.52 bound arms cell-1). More rod bivalents than the expected one out of seven, i.e. 30, 67 and 89% included rDNA-carrying chromosomes. Corresponding bound short arm frequencies were 0.89, 0.72 and 0.52, while long arms and arms of other chromosomes presented complete or near- complete association. The two heterogenomic hybrids had a less regular M-I (av. 8.04 bound arms cell-1) including 20% rDNA-carrying rods with bound arm frequencies of 0.29 in short and 0.87 in long arms. Positions of chromosome associations were established in all 150 rDNA-carrying bivalents. In 77 bivalents with short arm associations, 4% of these occurred proximally to, none at, and 96% distally to rDNA sites, i.e. in satellites. In 143 bivalents with long arm associations, 83% occurred at interstitial and 17% at terminal positions. The observations combine increased frequency of rDNA-carrying rods with decreased frequency of association at NOR regions of SAT-chromosomes. The basis for the relationship is discussed.
|
|
| 39. |
- Yamasaki, Y, et al.
(författare)
-
Mouse chromosome 19 and distal rat chromosome 1: a chromosome segment conserved in evolution.
- 2001
-
Ingår i: Hereditas. - : Wiley-Blackwell Publishing, Inc.. - 0018-0661 .- 1601-5223. ; 134:1, s. 23-34
-
Tidskriftsartikel (refereegranskat)abstract
- Through a combination of radiation hybrid mapping and studies by FISH and zoo-FISH we have made a comparative investigation of the distal portion of rat chromosome 1 (RNO1) and the entire mouse chromosome 19 (MMU19). It was found that homologous segments of RNO1 and MMU19 are similar in banding morphology and in length as determined by several different methods, and that the gene order of the 46 genes studied appears to be conserved across the homologous segments in the two species. High-resolution zoo-FISH techniques showed that MMU19 probes highlight only a continuous segment on RNO1 (1q43-qter), with no detectable signals on other rat chromosomes. We conclude that these data suggest the evolutionary conservation of a chromosomal segment from a common rodent ancestor. This segment now constitutes the entire MMU19 and a large segment distally on RNO1q in the mouse and rat, respectively.
|
|
| 40. |
- Widén, Björn, et al.
(författare)
-
Enzyme variation and inheritance in Glechoma hederacea (Lamiaceae), a diploidized tetraploid
- 2000
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 132:3, s. 229-241
-
Tidskriftsartikel (refereegranskat)abstract
- The chromosome number of the polyploid species Glechoma hederacea was found to be 2n = 36 in a sample of 93 ramets derived from 27 sites in N and C Europe. Variation in 10 enzymes was surveyed in material from S Sweden and S Czech Republic. The genetic control of variation was investigated using segregating progeny from crosses and self-fertilized heterozygous plants. The generic analysis comprised 30 of 32 putative alleles detected in the geographical survey. Five loci (Aat-2, Tpi-1, Tpi-2 Pgd-2 and Mnr) behaved as isoloci with one copy of a locus being monomorphic for a common allele, the other di-allelic for a common allele and a variant allele. In four isoloci (Pgd-1, Pgi-2, Mdh-2 and Adh), both copies of the duplicated locus were polymorphic, with one allele common to both copies and with another allele unique for each copy except for Pgd-1 where both copies were tri-allelic. Three loci, Pgm-3, Skd-1 and Skd-2 were regarded as being non-duplicated. Segregation ratios for all enzyme loci were in close agreement with expectations based on disomic inheritance. Our data suggest that the tetraploid G. hederaca is a diploidized autotetraploid.
|
|
| 41. |
- Allen, Marie, et al.
(författare)
-
High resolution genetic typing of the class II HLA-DRB1 locus using group-specific amplification and SSO-hybridisation in microplates
- 1998
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 129:2, s. 161-167
-
Tidskriftsartikel (refereegranskat)abstract
- The HLA-DRB1 locus is one of the most polymorphic HLA class II loci and rapid and accurate typing of this polymorphism is important both in bone-marrow transplantation, analysis of disease association and in forensic medicine. The allelic variation at DRB1 is characterized by combinations of a limited number of amino-acid motifs, reducing the resolution of a typing strategy based on a single PCR and subsequent analysis of polymorphic motifs. In the present paper we describe a strategy for typing of DRB1 based on eight allele-specific PCRs followed by sandwich hybridization to immobilized probes in a microplate format. The combined approach results in a rapid typing system with very high resolution. Using a rapid DNA extraction protocol, a complete HLA-DRB1 typing can be performed in less than a day.
|
|
| 42. |
- Cavelier, L, et al.
(författare)
-
MtDNA mutations in maternally inherited diabetes : presence of the 3397 ND1 mutation previously associated with Alzheimer's and Parkinson's disease
- 2001
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 135:1, s. 65-70
-
Tidskriftsartikel (refereegranskat)abstract
- Mutations in the mitochondrial tRNA(leu) (UUR) gene have been associated with diabetes mellitus and deafness. We screened for the presence of mtDNA mutations in the tRNA(leu) (UUR) gene and adjacent ND1 sequences in 12 diabetes mellitus pedigrees with a possible maternal inheritance of the disease. One patient carried a G to A substitution at nt 3243 (tRNA(leu) (UUR) gene) in heteroplasmic state. In a second pedigree a patient had an A to G substitution at nt 3397 in the ND1 gene. All maternal relatives of the proband had the 3397 substitution in homoplasmic state. This substitution was not present in 246 nonsymptomatic Caucasian controls. The 3397 substitution changes a highly conserved methionine to a valine at aa 31 and has previously been found in Alzheimer's (AD) and Parkinson's (PD) disease patients. Substitutions in the mitochondrial ND1 gene at aa 30 and 31 have associated with a number of different diseases (e.g. AD/PD, MELAS, cardiomyopathy and diabetes mellitus, LHON, Wolfram-syndrome and maternal inherited diabetes) suggesting that changes at these two codons may be associated with very diverse pathogenic processes. In a further attempt to search for mtDNA mutations outside the tRNAleu gene associated with diabetes, the whole mtDNA genome sequence was determined for two patients with maternally inherited diabetes and deafness. Except for substitutions previously reported as polymorphisms, none of the two patients showed any non-synonymous substitutions either in homoplasmic or heteroplasmic state. These results imply that the maternal inherited diabetes and deafness in these patients must result from alterations of nuclear genes and/or environmental factors.
|
|
| 43. |
- Enckell, P H, et al.
(författare)
-
The dispersal pattern of an anthropochorous species: Genetic variation in populations of Lumbricus terrestris L. (Lumbricidae) in the Faroe Islands
- 1986
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 104:2, s. 253-261
-
Tidskriftsartikel (refereegranskat)abstract
- Ten populations of the anthropochorous Lumbricus terrestris L. (Lumbricidae) from six islands in the Faroes were scored for enzyme variation by electrophoresis. The allele frequencies were analyzed by cluster analysis and information entropy relationships. There was a significant heterogeneity in allele frequencies among the samples. Four groups could be distinguished in the cluster analysis of which one was larger (at least five sites); two sites were defined as outliers. Information entropy showed that the allele frequency data were structured differently over the sites and that the most non-random site was also one of the outliers in the cluster space. The main group in the cluster analysis also forms a geographically central group in the islands. These results are discussed against the known colonization history of the Faroes. It is concluded that the genetic variation pattern does not indicate any single point of invasion of L. terrestris into the islands. Rather, it shows that former and present-day communications between the islands are responsible for similarities and dissimilarities in genetic variation in the L. terrestris populations.
|
|
| 44. |
- Lönn, Mikael, et al.
(författare)
-
Hybrids and fruit set in a mixed flowering-time population of Gymnadenia conopsea (Orchidaceae)
- 2006
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 143:1, s. 222-228
-
Tidskriftsartikel (refereegranskat)abstract
- We have recently found that the morphologically determined subspecies Gymnadenia conopsea ssp conopsea in Sweden includes early and late flowering individuals. We were interested in the interactions between the flowering time groups; if there were gene flow between them and if so this was detrimental or advantageous. A spatially mixed population of early and late flowering individuals was studied using three microsatellite loci. We measured patterns in genetic differentiation and inferred occurrence of hybridisation and introgression. Variation in flowering time, fertility and relative and absolute fruit set was measured. The pattern of introgression between flowering-time groups differed between loci. In two of the three investigated loci, allele separation was distinct between early and late flowering plants and one genetically obvious hybrid was infertile. In the third locus, several alleles were shared between the two flowering time variants. The degree of introgression was associated to fruit set failure, which was higher in the late flowering plants and lower in early flowering plants. A small group of early flowering individuals with somewhat delayed flowering compared to the main group was genetically distinct and had lower relative and absolute fruit set. This group was not genetically intermediate, but rather constituting an independent group, with lower fruit set possibly caused by absence of pollinators. There seem to be a strong barrier against introgression into the late flowering group which is kept genetically distinct and less diverse. The early flowering group is diverse, includes two subgroups and seems to benefit from gene flow.
|
|
| 45. |
- Nyberg Berglund, Anna Britt, et al.
(författare)
-
Two postglacial immigration lineages of the polyploid Cerastium alpinum (Caryophyllaceae)
- 2001
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 134:2, s. 171-183
-
Tidskriftsartikel (refereegranskat)abstract
- The plant cover of Fennoscandia is young because of the recent glaciation. This study covers the early stages of diversification and the genetic consequences of postglacial migration of a hermaphroditic polyploid plant, Cerastium alpinum. It has a continuous distribution in the alpine region, where it grows on alpine heaths and serpentine soils that are rich in heavy metals. Within the boreal forest C. alpinum has a scattered distribution on serpentine, dolomite and steep slopes. Plants from 31 populations in Norway, Sweden and Finland were subjected to enzyme electrophoresis. Analyses of the enzyme phenotypes suggest that C. alpinum has colonized Fennoscandia through two postglacial immigration events resulting in a southeastern and a southwestern lineage. These two lineages seem to meet in a hybrid zone in northern Sweden. Large genetic differences were found among most populations in both the southeastern and the southwestern lineages. This suggests that the populations are effectively isolated from each other.
|
|
| 46. |
- Sigvald, Roland
(författare)
-
Genetic analysis for some plant and fruit traits, and its implication for a breeding program of hot pepper (Capsicum annuum var. annuum L.)
- 2009
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 146, s. 131-140
-
Tidskriftsartikel (refereegranskat)abstract
- Two separate field experiments were conducted on hot pepper in which the genetic, heritability and environmental components of variation for seven plant and fruit traits in 78 genotypes and gene effects for four fruit traits in six generations of five crosses were estimated. The objectives were to determine the variation and effects of genes controlling inheritance of plant and fruit traits, and to propose efficient breeding procedures for improving the crop. Analysis of variance in half-diallel crosses revealed the presence of total genetic variability for seven traits among the 78 experimental entries with an excess of over-dominance genes. The presence of unequal distributions of dominant genes with positive and negative effects was observed among the parents and indicated the need to be cautious while selecting hot pepper parents for breeding purposes. Significant variability was also revealed in environmental sensitivity among the 78 experimental entries for some traits along with high heritability, which could be an advantage for a plant breeder but provides less clear opportunities for an agronomist to achieve better plant and fruit traits. Progeny generations (F(1), F(2), B(1) and B(2)) were found to perform better for fruit traits than their parents (P(1) and P(2)). The presence of significant gene interactions indicated a polygenic inheritance of the fruit traits studied and the possibility of pyramiding favorable alleles in the required directions at different levels of progeny generations. Heterosis, backcrossing, multiple crossing and pedigree breeding methods with recurrent selection may facilitate simultaneous exploitation of the genetic components and gene effects obtained. Nevertheless, it is doubtful whether selection efforts within the current set of hot pepper parents would be beneficial to achieve superior fruit traits for developing new varieties.
|
|
| 47. |
- Ståhl, Fredrik, et al.
(författare)
-
Amplification and overexpression of the mouse mdria gene in nine independently selected multidrug-resistant SEWA murine cell lines
- 1993
-
Ingår i: Hereditas. - : Wiley-Blackwell Publishing, Inc.. - 0018-0661 .- 1601-5223. ; 118:2, s. 121-130
-
Tidskriftsartikel (refereegranskat)abstract
- Many different drugs may be used in selecting cells for multidrug resistance (MDR). Enhanced expression and/or gene amplification is known to cause overproduction of membrane-bound 170,000 P-glycoproteins, responsible for the MDR. In rodents, the P-glycoproteins are encoded by a small gene family: mdr 1a, mdr 1b, and mdr2. To evaluate the relationship between the pattern of MDR and the selecting drug, nine MDR sublines were independently selected from a sensitive mouse tumor cell line, SEWATC13K, using three different drugs. Each MDR subline displayed amplification of one or more of the three mdr genes, but only one, mdr 1a, was consistently overexpressed. Thus, our results indicate that the pattern of mdr gene amplification and overexpression is independent of the selective agent. Furthermore, in four of the MDR sublines, where all three mdr genes had been originally amplified, pulsed field gel electrophoresis (PFGE) revealed that amplification of mdr 1a, only, was a second step of gene amplification. In addition, the gene for the calcium-binding protein, sorcin, was coamplified in eight of the nine MDR sublines. The sorcin gene was overexpressed in seven of these eight sublines. Finally, hybridizations with a probe homologous with a putative region of RFLP (restriction fragment length polymorphism), indicated that the amplified sequences originate from one or the other of the two homologous chromosomes with no preference.
|
|
| 48. |
- Von Bothmer, Roland
(författare)
-
Analysis of DNA sequence polymorphism at the cMWG699 locus reveals phylogenetic relationships and allopolyploidy within Hordeum murinum subspecies
- 2010
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 147, s. 34-42
-
Tidskriftsartikel (refereegranskat)abstract
- Hordeum murinum L. is one of the most widely distributed species in the genus Hordeum. This species is composed of three subspecies with three ploidy levels, namely subsp. glaucum (2x=14), subsp. murinum (4x=28) and subsp. leporinum (4x=28, 6x=42). These three subspecies are morphologically similar and are frequently referred to as the 'murinum complex'. Although many cytological studies suggest that the murinum complex is allopolyploid, one inter-specific hybridization study suggested that it is autopolyploid. The goals of the present study are to identify nucleotide variation in the cMWG699 locus in the polyploid genomes of the murinum complex, to conduct molecular phylogenetic analysis of this locus, and to clarify the allo- versus auto-polyploidy status of the murinum complex. For this purpose, PCR-RFLP analysis was conducted with HhaI and SspI restriction enzymes on 80 H. murinum accessions. Single enzyme digestion data revealed polymorphism between diploid and polyploids, and double-digestion revealed polymorphism between tetra- and hexaploids. The nucleotide sequences of clones clearly show that polyploid murinum species are allopolyploid. In addition, DNA sequence analysis indicated that one donor of the tetraploid was subsp. glaucum (2x), as has been suggested previously by cytological studies. The other diploid donors were not identified, but at least one group of sequences common to 4x and 6x genomes (namely clonetype B) was highly diverged from 2x subsp. glaucum. The two tetraploid subspecies, 4x subsp. murinum and 4x subsp. leporinum, had identical DNA sequences, suggesting that these two subspecies are not differentiated at the cMWG699 locus.
|
|
| 49. |
- Árnason, Úlfur, et al.
(författare)
-
The reversal of human phylogeny : Homo left Africa as erectus, came back as sapiens sapiens
- 2020
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 157:1
-
Forskningsöversikt (refereegranskat)abstract
- Background: The molecular out of Africa hypothesis, OOAH, has been considered as an established fact amid population geneticists for some 25–30 years despite the early concern with it among phylogeneticists with experience beyond that of Homo. The palaeontological support for the hypothesis is also questionable, a circumstance that in the light of expanding Eurasian palaeontological knowledge has become accentuated through the last decades. Results: The direction of evolution in the phylogenetic tree of modern humans (Homo sapiens sapiens, Hss) was established inter alia by applying progressive phylogenetic analysis to an mtDNA sampling that included a Eurasian, Lund, and the African Mbuti, San and Yoruba. The examination identified the African populations as paraphyletic, thereby compromising the OOAH. The finding, which was consistent with the out of Eurasia hypothesis, OOEH, was corroborated by the mtDNA introgression from Hss into Hsnn (Neanderthals) that demonstrated the temporal and physical Eurasian coexistence of the two lineages. The results are consistent with the palaeontologically established presence of H. erectus in Eurasia, a Eurasian divergence between H. sapiens and H. antecessor ≈ 850,000 YBP, an Hs divergence between Hss and Hsn (Neanderthals + Denisovans) ≈ 800,000 YBP, an mtDNA introgression from Hss into Hsnn* ≈ 500,000 YBP and an Eurasian divergence among the ancestors of extant Hss ≈ 250,000 YBP at the exodus of Mbuti/San into Africa. Conclusions: The present study showed that Eurasia was not the receiver but the donor in Hss evolution. The findings that Homo left Africa as erectus and returned as sapiens sapiens constitute a change in the understanding of Hs evolution to one that conforms to the extensive Eurasian record of Hs palaeontology and archaeology.
|
|
| 50. |
- Árnason, Úlfur
(författare)
-
The unidirectional phylogeny of Homo sapiens anchors the origin of modern humans in Eurasia
- 2021
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 158:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The Out of Africa hypothesis, OOAH, was challenged recently in an extended mtDNA analysis, PPA (Progressive Phylogenetic Analysis), that identified the African human populations as paraphyletic, a finding that contradicted the common OOAH understanding that Hss had originated in Africa and invaded Eurasia from there. The results were consistent with the molecular Out of Eurasia hypothesis, OOEH, and Eurasian palaeontology, a subject that has been largely disregarded in the discussion of OOAH. Results: In the present study the mtDNA tree, a phylogeny based on maternal inheritance, was compared to the nuclear DNA tree of the paternally transmitted Y-chromosome haplotypes, Y-DNAs. The comparison showed full phylogenetic coherence between these two separate sets of data. The results were consistent with potentially four translocations of modern humans from Eurasia into Africa, the earliest taking place ≈ 250,000 years before present, YBP. The results were in accordance with the postulates behind OOEH at the same time as they lent no support to the OOAH. Conclusions: The conformity between the mtDNA and Y-DNA phylogenies of Hss is consistent with the understanding that Eurasia was the donor and not the receiver in human evolution. The evolutionary problems related to OOAH became similarly exposed by the mtDNA introgression that took place from Hss into Neanderthals ≈ 500,000 YBP, a circumstance that demonstrated the early coexistence of the two lineages in Eurasia.
|
|
