| 1. |
- Kvarnemo, C., et al.
(författare)
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Evidence of paternal nutrient provisioning to embryos in broad-nosed pipefish Syngnathus typhle
- 2011
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 78:6, s. 1725-1737
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Tidskriftsartikel (refereegranskat)abstract
- In two experiments, radioactively labelled nutrients (either H-3-labelled amino-acid mixture or C-14-labelled glucose) were tube-fed to brooding male Syngnathus typhle. Both nutrients were taken up by the males and radioactivity generally increased in the brood pouch tissue with time. Furthermore, a low but significant increase of H-3-labelled amino acids in embryos was found over the experimental interval (48 h), whereas in the C-14-glucose experiment the radioactivity was taken up by the embryos but did not increase over the experimental time (320 min). Uptake of radioisotopes per embryo did not differ with embryo size. A higher uptake mg(-1) tissue of both H-3-labelled amino acids and C-14-labelled glucose was found in smaller embryos, possibly due to a higher relative metabolic rate or to a higher surface-area-to-volume ratio compared to larger embryos. Uptake in embryos was not influenced by male size, embryonic developmental advancement or position in the brood pouch. It is concluded that brooding males provide amino acids, and probably also glucose, to the developing embryos in the brood pouch.
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| 2. |
- Kvarnemo, Charlotta, 1963, et al.
(författare)
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Evidence of paternal nutrient provisioning to embryos in the pipefish Syngnathus typhle
- 2011
-
Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112. ; 78:6, s. 1725-1737
-
Tidskriftsartikel (refereegranskat)abstract
- In two experiments, radioactively labelled nutrients (either 3H-labelled amino-acid mixture or 14Clabelled glucose) were tube-fed to brooding male Syngnathus typhle. Both nutrients were taken up by the males and radioactivity generally increased in the brood pouch tissue with time. Furthermore, a low but significant increase of 3H-labelled amino acids in embryos was found over the experimental interval (48 h), whereas in the 14C-glucose experiment the radioactivity was taken up by the embryos but did not increase over the experimental time (320 min). Uptake of radioisotopes per embryo did not differ with embryo size. A higher uptake mg−1 tissue of both 3H-labelled amino acids and 14C-labelled glucose was found in smaller embryos, possibly due to a higher relative metabolic rate or to a higher surface-area-to-volume ratio compared to larger embryos. Uptake in embryos was not influenced by male size, embryonic developmental advancement or position in the brood pouch. It is concluded that brooding males provide amino acids, and probably also glucose, to the developing embryos in the brood pouch.
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| 3. |
- Mobley, Kenyon B.
(författare)
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Grandfathering in a new era of parentage analysis
- 2011
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 20:6, s. 1080-1082
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Tidskriftsartikel (refereegranskat)abstract
- The advent of DNA fingerprinting and microsatellite techniques has revolutionized the way in which we investigate genetic pedigrees in the wild (Pemberton 2008). With large and often incomplete data sets consisting of hundreds to thousands of individuals over multiple generations becoming commonplace, new methods in parentage analysis are being developed to rise to the next generation of questions and challenges. In this issue, Christie et al. (2011) provide a simple yet elegant solution to the problem of identifying missing parents and assessing hybrid fitness in a mixed population of wild and hatchery steelhead trout (Oncorhynchus mykiss) where not all individuals can be sampled effectively. They develop a new method of grandparent analysis where parental genotypes can be reconstructed using data from candidate grandparent crosses and F2 offspring genotypes, allowing for new explorations of hybridization, migration and gene flow in wild populations.
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| 4. |
- Mobley, Kenyon B., et al.
(författare)
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Morphological and genetic divergence in Swedish postglacial stickleback (Pungitius pungitius) populations
- 2011
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Ingår i: BMC Evolutionary Biology. - London : BioMed Central. - 1471-2148. ; 11, s. 287-
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Tidskriftsartikel (refereegranskat)abstract
- Background: An important objective of evolutionary biology is to understand the processes that govern phenotypic variation in natural populations. We assessed patterns of morphological and genetic divergence among coastal and inland lake populations of nine-spined stickleback in northern Sweden. Coastal populations are either from the Baltic coast (n = 5) or from nearby coastal lakes (n = 3) that became isolated from the Baltic Sea (< 100 years before present, ybp). Inland populations are from freshwater lakes that became isolated from the Baltic approximately 10,000 ybp; either single species lakes without predators (n = 5), or lakes with a recent history of predation (n = 5) from stocking of salmonid predators (~50 ybp).Results: Coastal populations showed little variation in 11 morphological traits and had longer spines per unit of body length than inland populations. Inland populations were larger, on average, and showed greater morphological variation than coastal populations. A principal component analysis (PCA) across all populations revealed two major morphological axes related to spine length (PC1, 47.7% variation) and body size (PC2, 32.9% variation). Analysis of PCA scores showed marked similarity in coastal (Baltic coast and coastal lake) populations. PCA scores indicate that inland populations with predators have higher within-group variance in spine length and lower within-group variance in body size than inland populations without predators. Estimates of within-group PST (a proxy for QST) from PCA scores are similar to estimates of FST for coastal lake populations but PST > FST for Baltic coast populations. PST > FST for PC1 and PC2 for inland predator and inland no predator populations, with the exception that PST < FST for body size in inland populations lacking predators.Conclusions: Baltic coast and coastal lake populations show little morphological and genetic variation within and between groups suggesting that these populations experience similar ecological conditions and that time since isolation of coastal lakes has been insufficient to demonstrate divergent morphology in coastal lake populations. Inland populations, on the other hand, showed much greater morphological and genetic variation characteristic of long periods of isolation. Inland populations from lakes without predators generally have larger body size, and smaller spine length relative to body size, suggesting systematic reduction in spine length. In contrast, inland populations with predators exhibit a wider range of spine lengths relative to body size suggesting that this trait is responding to local predation pressure differently among these populations. Taken together the results suggest that predation plays a role in shaping morphological variation among isolated inland populations. However, we cannot rule out that a causal relationship between predation versus other genetic and environmental influences on phenotypic variation not measured in this study exists, and this warrants further investigation.
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| 5. |
- Mobley, Kenyon B., et al.
(författare)
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The effect of maternal body size on embryo survivorship in the broods of pregnant male pipefish
- 2011
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 65:6, s. 1169-1177
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of male pregnancy in the family Syngnathidae (seahorses, pipefishes, and sea dragons) provides an exceptionally fertile system in which to investigate issues related to the evolution of parental care. Here, we take advantage of this unique reproductive system to study the influence of maternal body size on embryo survivorship in the brood pouches of pregnant males of the broad-nosed pipefish, Syngnathus typhle. Males were mated with either two large females, two small females, a large then a small female, or a small then a large female. Our results show that offspring survivorship depends on an interaction between female body size and the number of eggs transferred by the female. Eggs of larger females deposited in large numbers are more likely to result in viable offspring than eggs of smaller females laid in large numbers. However, when females deposited smaller numbers of eggs, the eggs from smaller females were more likely to produce viable offspring compared to those from larger females. We found no evidence that this result was based on mating order, the relative sizes of competing females, or egg characteristics such as dry weight of eggs. Additionally, male body size did not significantly influence the survivorship of offspring during brooding. Our results suggest that the factors underlying offspring survivorship in pipefish may be more complex than previously believed, with multiple factors interacting to determine the fitness of individual offspring within the broods of pregnant males.
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| 6. |
- Mobley, Kenyon B., et al.
(författare)
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The genetics and genomics of Syngnathidae : pipefishes, seahorses and seadragons.
- 2011
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 78:6, s. 1624-1646
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Forskningsöversikt (refereegranskat)abstract
- The goal of this review was to provide a historical overview of how molecular techniques have increased the understanding of the ecology and evolution of the family Syngnathidae (pipefishes, seahorses and seadragons). Molecular studies based primarily on mitochondrial DNA markers have proved their worth by elucidating complex phylogenetic relationships within the family. Phylogeographic studies, which have revealed how life-history traits and past climatic events shape geographic distributions and patterns of genetic variation within syngnathid species, also provide interesting case studies for the conservation and management of threatened species. The application of microsatellite DNA markers has opened a floodgate of studies concerned with the breeding biology of these fishes, which are interesting due to their unique reproductive mode of male pregnancy. Research in this area has contributed significantly to the understanding of mating patterns and sexual selection. Molecular markers may also be employed in studies of demography, migration and local breeding population sizes. Genomic studies have identified genes that are probably involved in male pregnancy and promise additional insights into various aspects of syngnathid biology at the level of the gene. Despite these advances, much more remains to be explored. Goals for future research should include: (1) a more inclusive phylogeny to resolve outstanding issues concerning the relationships within the family and higher order taxa, (2) a broader use of molecular studies to aid management and conservation efforts, (3) the inclusion of more genera in comparative behavioural studies and (4) the continued development of genomic resources for syngnathids to facilitate comparative genomic work.
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