| 1. |
- Arnqvist, Göran, et al.
(author)
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Negative frequency dependent selection on sympatric mtDNA haplotypes in Drosophila subobscura
- 2016
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 153
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Journal article (peer-reviewed)abstract
- Background: Recent experimental evidence for selection on mitochondrial DNA (mtDNA) has prompted the question as to what processes act to maintain within-population variation in mtDNA. Balancing selection though negative frequency dependent selection (NFDS) among sympatric haplotypes is a possibility, but direct empirical evidence for this is very scarce. Findings: We extend the previous findings of a multi-generation replicated cage experiment in Drosophila subobscura, where mtDNA polymorphism was maintained in a laboratory setting. First, we use a set of Monte Carlo simulations to show that the haplotype frequency dynamics observed are inconsistent with genetic drift alone and most closely match those expected under NFDS. Second, we show that haplotype frequency changes over time were significantly different from those expected under either genetic drift or positive selection but were consistent with those expected under NFSD. Conclusions: Collectively, our analyses provide novel support for NFDS on mtDNA haplotypes, suggesting that mtDNA polymorphism may at least in part be maintained by balancing selection also in natural populations. We very briefly discuss the possible mechanisms that might be involved.
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| 2. |
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| 3. |
- Bengtsson, Bengt Olle
(author)
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Strange history: the fall of Rome explained in Hereditas.
- 2014
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In: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 151:6, s. 132-139
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Journal article (peer-reviewed)abstract
- In 1921 Hereditas published an article on the fall of Rome written by the famous classical scholar Martin P:son Nilsson. Why was a paper on this unexpected topic printed in the newly founded journal? To Nilsson, the demise of the Roman Empire was explained by the "bastardization" occurring between "races" from different parts of the realm. Offspring from mixed couples were of a less stable "type" than their parents, due to the breaking up by recombination of the original hereditary dispositions, which led to a general loss of competence to rule and govern. Thus, the "hardness" of human genes, together with their recombination, was - according to Nilsson - the main cause of the fall of Rome. Nilsson's argument is not particularly convincingly presented. Human "races" are taken to have the same genetic structure as inbred crop strains, and Nilsson believes in a metaphysical unity between the individual and the race to which it belongs. However, in my view, Martin P:son Nilsson and his friend Herman Nilsson-Ehle had wider aims with the article than to explain a historical event. The article can be read as indicating strong support from the classical human sciences to the ambitious new science of genetics. Support is also transferred from genetics to the conservative worldview, where the immutability and inflexibility of the Mendelian genes are used to strengthen the wish for greater stability in politics and life. The strange article in Hereditas can, thus, be read as an early instance in the - still ongoing - tug-of-war between the conservative and the liberal ideological poles over how genetic results best are socially interpreted.
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| 4. |
- Brown, Keith S., Jr., et al.
(author)
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Chromosomal evolution in the South American Riodinidae (Lepidoptera Papilionoidea)
- 2012
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 149:4, s. 128-138
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Journal article (peer-reviewed)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.
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| 5. |
- Castillejo-Lopez, Casimiro, et al.
(author)
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Drosophila exoribonuclease nibbler is a tumor suppressor, acts within the RNA(i) machinery and is not enriched in the nuage during early oogenesis
- 2017
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In: Hereditas. - : BIOMED CENTRAL LTD. - 0018-0661 .- 1601-5223. ; 155
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Journal article (peer-reviewed)abstract
- Background: micro RNAs (miRNAs) are important regulators of many biological pathways. A plethora of steps are required to form, from a precursor, the mature miRNA that eventually acts on its target RNA to repress its expression or to inhibit translation. Recently, Drosophila nibbler (nbr) has been shown to be an important player in the maturation process of miRNA and piRNA. Nbr is an exoribonuclease which helps to shape the 3' end of miRNAs by trimming the 3' overhang to a final length. Results: In contrast to previous reports on the localization of Nbr, we report that 1) Nbr is expressed only during a short time of oogenesis and appears ubiquitously localized within oocytes, and that 2) Nbr was is not enriched in the nuage where it was shown to be involved in piwi-mediated mechanisms. To date, there is little information available on the function of nbr for cellular and developmental processes. Due to the fact that nbr mutants are viable with minor deleterious effects, we used the GAL4/UAS over-expression system to define novel functions of nbr. We disclose hitherto unknown functions of nbr 1) as a tumor suppressor and 2) as a suppressor of RNAi. Finally, we confirm that nbr is a suppressor of transposon activity. Conclusions: Our data suggest that nbr exerts much more widespread functions than previously reported from trimming 3' ends of miRNAs only.
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| 6. |
- Crespo, Leonardo, et al.
(author)
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A systematic review of rye (Secale cereale L.) as a source of resistance to pathogens and pests in wheat (Triticum aestivum L.)
- 2017
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 154, s. 1-9
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Research review (peer-reviewed)abstract
- Wheat is globally one of the most important crops. With the current human population growth rate, there is an increasing need to raise wheat productivity by means of plant breeding, along with development of more efficient and sustainable agricultural systems. Damage by pathogens and pests, in combination with adverse climate effects, need to be counteracted by incorporating new germplasm that makes wheat more resistant/tolerant to such stress factors. Rye has been used as a source for improved resistance to pathogens and pests in wheat during more than 50 years. With new devastating stem and yellow rust pathotypes invading wheat at large acreage globally, along with new biotypes of pest insects, there is renewed interest in using rye as a source of resistance. Currently the proportion of wheat cultivars with rye chromatin varies between countries, with examples of up to 34%. There is mainly one rye source, Petkus, that has been widely exploited and that has contributed considerably to raise yields and increase disease resistance in wheat. Successively, the multiple disease resistances conferred by this source has been overcome by new pathotypes of leaf rust, yellow rust, stem rust and powdery mildew. However, there are several other rye sources reported to make wheat more resistant to various biotic constraints when their rye chromatin has been transferred to wheat. There is also development of knowledge on how to produce new rye translocation, substitution and addition lines. Here we compile information that may facilitate decision making for wheat breeders aiming to transfer resistance to biotic constraints from rye to elite wheat germplasm.
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| 7. |
- Czerniejewski, P., et al.
(author)
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Molecular connectedness between self and none self-sustainable populations of Chinese mitten crab (Eriocheir sinensis, H. Milne Edwards, 1853) with focus to the Swedish Lake Vanern and the Oder and Vistula River in Poland
- 2012
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661. ; 149:2, s. 55-61
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Journal article (peer-reviewed)abstract
- The highly invasive Chinese mitten crabs (Eriocheir sinensis) was studied to reveal the genetic relationship between three none self-sustainable population within the Polish Oder and Vistula River and Lake Vanern in Sweden. Crabs from self-sustainable populations were collected from the Elbe River (Germany), San Francisco Bay (USA) and five Asian river estuaries. Both parsimony and maximum likelihood analysis of the nuclear ITS 1 and ITS 2 regions reveal a similar topological pattern. The mitochondrial cytochrome c oxidase subunit I (COI) sequence had too low resolution to be informative. The Oder River haplotypes showed high sequence similarities to both the Elbe population and/or the native spawning areas in China. The Vistula River showed haplotypic similarity to specimens from the Oder River in Poland or the Elbe River. Also high sequence similarities were observed to the specimens from the Swedish Lake Vanern indicating to an origin from the River Elbe. Minor changes in evolutionary interpretation exist depending on how gaps are treated and the analytic method. There is a complex movement involving back and forth transoceanic colonization of the Chinese mitten crab haplotypes. Invasion routes are discussed in relation to ship transfer routes and canal waterways.
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| 8. |
- Dida, Mulatu Geleta, et al.
(author)
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Genetic diversity in sorghum (Sorghum bicolor (L.) Moench) accessions of Zambia as revealed by simple sequence repeats (SSR)
- 2011
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 148, s. 52-62
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Journal article (peer-reviewed)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.
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| 9. |
- Edin, Eva, et al.
(author)
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Genetic diversity and occurrence of the F129L substitutions among isolates of Alternaria solani in south-eastern Sweden
- 2016
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 153
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Journal article (peer-reviewed)abstract
- Background: Early blight, caused by the fungus Alternaria solani, occurs on potato mainly in the south-eastern part of Sweden, but also in other parts of the country. The aim of this study was to investigate the genetic diversity of A. solani populations from different potato growing regions in south-eastern Sweden using AFLP marker analysis. In addition, the cultured isolates were examined for substitutions in the gene encoding cytochrome b, associated with loss of sensitivity against QoI fungicides.Results: Nei's gene diversity index for the Swedish populations of A. solani revealed a gene diversity of up to 0.20. Also genetic differentiation was observed among populations of A. solani from different locations in south-eastern Sweden. The mitochondrial genotype of the isolates of A. solani was determined and both known genotypes, GI (genotype 1) and GII (genotype 2), were found among the isolates. The occurrence of the F129L substitution associated with a loss of sensitivity to strobilurins was confirmed among the GII isolates. In vitro conidial germination tests verified that isolates containing the F129L substitution had reduced sensitivity to azoxystrobin and, at a lower extent, to pyraclostrobin.Conclusions: Genetic diversity was relatively high among isolates of A. solani in south-eastern part of Sweden. F129L substitutions, leading to reduced sensitivity to strobilurins, have been established in field populations, which may have implications for the future efficacy of QoI fungicides.
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| 10. |
- Englund, Thomas, et al.
(author)
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Relatedness and diversity of nine Swedish local chicken breeds as indicated by the mtDNA D-loop
- 2014
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In: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 151, s. 229-233
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Journal article (peer-reviewed)abstract
- In this study part of the mitochondrial D-loop was sequenced in a total of 40 samples from nine Swedish local chicken breeds. Among our 40 samples we observed 15 segregating sites and seven different haplotypes. The most common haplotype was present in all investigated individuals in fi ve breeds and together with other haplotypes in three breeds. This haplotype is common in domestic chickens and has been found in both local and commercial breeds in many parts of the world. The breed Ö landsh ö na was most different from the other Swedish breeds with all three individuals sharing a haplotype that differed from the most common haplotype at nine of the 15 segregating sites.
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