Isolated Population

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Yurii S. Aulchenko - One of the best experts on this subject based on the ideXlab platform.

  • Genetic variation in the KIF1B locus influences susceptibility to multiple sclerosis.
    Nature genetics, 2008
    Co-Authors: Yurii S. Aulchenko, I A Hoppenbrouwers, Sreeram V. Ramagopalan, Linda Broer, Naghmeh Jafari, Jan Hillert, Jenny Link, Wangko Lundström, Eva Greiner, A. Dessa Sadovnick
    Abstract:

    Rogier Hintzen and colleagues report the results of a search for genetic variants associated with susceptibility to multiple sclerosis in a genetically Isolated Population that lead to identification of a new susceptibility locus in the region of the KIF1B gene on chromosome 1.

  • The Effect of Genetic Drift in a Young Genetically Isolated Population
    Annals of Human Genetics, 2005
    Co-Authors: Luba M Pardo, Ian Mackay, Ben A Oostra, Cornelia M. Van Duijn, Yurii S. Aulchenko
    Abstract:

    The genetic make-up of genetically Isolated Populations may differ from a general Population as a result of genetic drift and founder effects. We assessed the extent of this deviation in a recently Isolated Population located in the southwest of the Netherlands and studied as part of the Genetic Research in Isolated Population (GRIP) program. A gene-dropping experiment was performed in a large pedigree from this isolate, assuming different initial frequencies in the Population founders came from. Allelic frequencies in the last generations of this pedigree were estimated. Simulation analysis showed large fluctuations, as measured by variation coefficient and sufficient loss probability, when initial frequencies were lower than or equal to 1%. For initial frequencies larger than 1% the fluctuations were small. We also analyzed mean heterozygosity and allele diversity of 592 markers in a random sample from the GRIP Population. The results were compared with a general Population (CEPH sample), old large isolate (Icelandic sample) and the small-sized Population of Talana (Sardinia). GRIP mean heterozygosity and mean number of alleles were significantly lower as compared with CEPH and Iceland, but much higher when compared with the Talana Population. We also concluded that the findings from the GRIP Population for common variants (>1%) are likely to be extendable to other young isolates in Europe as well as to outbred Populations.

  • the effect of genetic drift in a young genetically Isolated Population
    Annals of Human Genetics, 2005
    Co-Authors: Luba M Pardo, Ian Mackay, Ben A Oostra, Cornelia M Van Duijn, Yurii S. Aulchenko
    Abstract:

    Summary The genetic make-up of genetically Isolated Populations may differ from a general Population as a result of genetic drift and founder effects. We assessed the extent of this deviation in a recently Isolated Population located in the southwest of the Netherlands and studied as part of the Genetic Research in Isolated Population (GRIP) program. A gene-dropping experiment was performed in a large pedigree from this isolate, assuming different initial frequencies in the Population founders came from. Allelic frequencies in the last generations of this pedigree were estimated. Simulation analysis showed large fluctuations, as measured by variation coefficient and sufficient loss probability, when initial frequencies were lower than or equal to 1%. For initial frequencies larger than 1% the fluctuations were small. We also analyzed mean heterozygosity and allele diversity of 592 markers in a random sample from the GRIP Population. The results were compared with a general Population (CEPH sample), old large isolate (Icelandic sample) and the small-sized Population of Talana (Sardinia). GRIP mean heterozygosity and mean number of alleles were significantly lower as compared with CEPH and Iceland, but much higher when compared with the Talana Population. We also concluded that the findings from the GRIP Population for common variants (>1%) are likely to be extendable to other young isolates in Europe as well as to outbred Populations.

  • A Genome-Wide Search for Genes Involved in Type 2 Diabetes in a Recently Genetically Isolated Population From the Netherlands
    Diabetes, 2003
    Co-Authors: Yurii S. Aulchenko, Norbert Vaessen, Peter Heutink, Jan Pullen, P.j.l.m. Snijders, Albert Hofman, Lodewijk A. Sandkuijl, Jeanine J. Houwing-duistermaat, Mark Edwards, Simon T. Bennett
    Abstract:

    Multiple genes, interacting with the environment, contribute to the susceptibility to type 2 diabetes. We performed a genome-wide search to localize type 2 diabetes susceptibility genes in a recently genetically Isolated Population in the Netherlands. We identified 79 nuclear families with type 2 diabetes who were related within 13 generations and performed a 770-marker genome-wide scan search for shared founder alleles. Twenty-six markers yielded a logarithm of odds (LOD) score >0.59 (nominal P 1.17 (nominal P < 0.01). The strongest evidence for a type 2 diabetes locus was at marker D18S63 on chromosome 18p (LOD 2.3, P = 0.0006). This region was investigated further using additional markers. For one of these markers (D18S1105), we found a significant association with type 2 diabetes (odds ratio 6.7 [95% CI 1.5-30.7], P = 0.005 for the 97-bp allele, assuming a dominant model), which increased when limiting the analysis to patients with high BMI (12.25 [2.1-71], P = 0.003). A locus on chromosome 18p in patients with high BMI was suggested earlier by Parker et al. Our study is the first to confirm this locus.

H.p. Koelewijn - One of the best experts on this subject based on the ideXlab platform.

Isabelle Delisle - One of the best experts on this subject based on the ideXlab platform.

  • History and fate of a small Isolated Population of Weddell seals at White Island, Antarctica
    Conservation Genetics, 2010
    Co-Authors: Thomas S. Gelatt, Corey S. Davis, Ian Stirling, Donald B. Siniff, Curtis Strobeck, Isabelle Delisle
    Abstract:

    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.

Thomas S. Gelatt - One of the best experts on this subject based on the ideXlab platform.

  • History and fate of a small Isolated Population of Weddell seals at White Island, Antarctica
    Conservation Genetics, 2010
    Co-Authors: Thomas S. Gelatt, Corey S. Davis, Ian Stirling, Donald B. Siniff, Curtis Strobeck, Isabelle Delisle
    Abstract:

    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.

Jacob Höglund - One of the best experts on this subject based on the ideXlab platform.

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