Transferrin Polymorphism and Population Structure of the Weddell Seal Leptonychotes Weddelli ( Lesson )

Shaughnessay, PD

doi:10.1071/bi9691581

Cited by 17 publications

(6 citation statements)

References 4 publications

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“…This population, known since the late 1950s (Heine 1960), is hypothesized to have been founded around that time by migrants from the nearby Erebus Bay (Stirling 1966). Absence of protein differentiation between the White Island and Erebus Bay populations (Shaughnessy 1969), based on samples collected during the 1960s, supports that idea. The ice shelf physically obstructs the passage to open water in Erebus Bay, and therefore the White Island population is thought to have been isolated from other populations ever since the time of its discovery.…”

Section: Introductionsupporting

confidence: 66%

History and fate of a small isolated population of Weddell seals at White Island, Antarctica

et al. 2009

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Weddell seals (Leptonychotes weddellii Lesson) at White Island, Antarctica form a small, completely enclosed, natural population hypothesized to be of recent origin, likely founded by individuals from nearby Erebus Bay. This population constitutes an ideal model to document a founder event and ensuing genetic drift, with implications for conservation. Here we combined historical accounts, census and tagging data since the late 1960s, and genetic data (41 microsatellite loci and mitochondrial DNA sequences) from 84 individuals representing nearly all individuals present between 1990 and 2000 to investigate the history of the founding of the White Island population, document its population dynamics and evaluate possible future threats. We fully resolved parental relationships over three overlapping generations. Cytonuclear disequilibrium among the first generation suggested that it comprised the direct descendants of a founding group. We estimated that the White Island population was founded by a small group of individuals that accessed the island during a brief break in the surrounding sea ice in the mid-1950s, consistent with historical accounts. Direct and indirect methods of calculating effective population size were highly congruent and suggested a minimum founding group consisting of three females and two males. The White Island population showed altered reproductive dynamics compared to Erebus Bay, including highly skewed sex ratio, documented inbred mating events, and the oldest known reproducing Weddell seals. A comparison with the putative source population showed that the White Island population has an effective inbreeding coefficient (F e ) of 0.29. Based on a pedigree analysis including the hypothesized founding group, 86% of the individuals for whom parents were known had inbreeding coefficients ranging 0.09-0.31. This high level of inbreeding was correlated with reduced pup survival. Seals at White Island therefore face the combined effects of low genetic variability, lack of immigration, and inbreeding depression. Ultimately, this study provides evidence of the effects of natural isolation on a large, long-lived vertebrate and can provide clues to the potential effects of anthropogenic-caused isolation of similar taxa.

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Section: Introductionsupporting

confidence: 66%

History and fate of a small isolated population of Weddell seals at White Island, Antarctica

et al. 2009

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“…However, some of those who have obtained sufficient numbers of samples from other species of seals, have found transferrin polymorphisms, for example Naevdal(1966a,b) found them in Harp and Ringed seals. Shaughnessy (1969) observed three transferrin types in the Weddell seal and a heterozygote deficiency which, in a population of 900 breeding females and 100 males, supported the suggestion already made by Stirling (1968) that the population was divided into breeding isolates. Shaughnessy (1970) described six transferrin types in southern Fur seals, (Arctocephalus spp.…”

Section: Discussionsupporting

confidence: 81%

Serum protein analysis of Grey seals

Heath

1978

Mammal Review

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Electrophoresis provides extensive information about species relationships and subspecific structure, because taxonomically separated species are unlikely to share electrophoretic characters. The technique is best for relatively immobile species and so far fish or marine mammals have proved difficult subjects; but if interbreeding occurs only at the edges of otherwise discrete populations the technique should detect this. Transferrin polymorphism!: in geographically separated populations of Weddell and southern Fur seals have been found.Because the Grey seal returns to the same distinct localities to breed, for instance the Orkneys, Shetlands, Farnes, North Rona, Hebrides, Wales and S.W. England, it seems sensible to seek such polymorphisms in this species.In my work serum samples from eight Orkney Grey seals and thirteen Farne seals were separated on horizontal starch gels, but no polymorphisrns were found. Such a small sample is however, not likely to reveal distinct or striking polymorphism.However, a study conducted on a wider scale and with larger samples, might reveal such polymorphisms, particularly in respect of transferrins, a possibility which was suggested during the course of my work.

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“…This site fidelity may lead to the development of subgroups of Weddell seals at certain locations Studies of gene frequencies in Weddell seals sampled at widely separated localities substantiate this idea (Shaughnessy, 1969;Seal et al, 1971a). d.…”

Section: Stock Identificationmentioning

confidence: 97%

Review of information regarding the conservation of living resources of the Antarctic marine ecosystem : final report / John L. Bengtson.

Bengtson¹

1978

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Transferrin Polymorphism and Population Structure of the Weddell Seal Leptonychotes Weddelli ( Lesson )

Cited by 17 publications

References 4 publications

History and fate of a small isolated population of Weddell seals at White Island, Antarctica

History and fate of a small isolated population of Weddell seals at White Island, Antarctica

Serum protein analysis of Grey seals

Review of information regarding the conservation of living resources of the Antarctic marine ecosystem : final report / John L. Bengtson.

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