Animal Breeding and Genetics Group, Department of Animal Sciences, University of Goettingen, Goettingen, Germany.
Center for Integrated Breeding Research, Department of Animal Sciences, University of Goettingen, Goettingen, Germany.
Genet Sel Evol. 2021 Apr 14;53(1):36. doi: 10.1186/s12711-021-00628-z.
Migration of a population from its founder population is expected to cause a reduction of its genetic diversity and facilitates differentiation between the population and its founder population, as predicted by the theory of genetic isolation by distance. Consistent with that theory, a model of expansion from a single founder predicts that patterns of genetic diversity in populations can be explained well by their geographic expansion from their founders, which is correlated with genetic differentiation.
To investigate this in chicken, we estimated the relationship between the genetic diversity of 160 domesticated chicken populations and their genetic distances to wild chicken populations.
Our results show a strong inverse relationship, i.e. 88.6% of the variation in the overall genetic diversity of domesticated chicken populations was explained by their genetic distance to the wild populations. We also investigated whether the patterns of genetic diversity of different types of single nucleotide polymorphisms (SNPs) and genes are similar to that of the overall genome. Among the SNP classes, the non-synonymous SNPs deviated most from the overall genome. However, genetic distance to the wild chicken still explained more variation in domesticated chicken diversity across all SNP classes, which ranged from 83.0 to 89.3%.
Genetic distance between domesticated chicken populations and their wild relatives can predict the genetic diversity of the domesticated populations. On the one hand, genes with little genetic variation across populations, regardless of the genetic distance to the wild population, are associated with major functions such as brain development. Changes in such genes may be detrimental to the species. On the other hand, genetic diversity seems to change at a faster rate within genes that are associated with e.g. protein transport and protein and lipid metabolic processes. In general, such genes may be flexible to changes according to the populations' needs. These results contribute to the knowledge of the evolutionary patterns of different functional genomic regions in the chicken.
根据遗传隔离距离理论的预测，人口从其发源地迁移会导致其遗传多样性减少，并促进其与发源地人口的分化。一致的理论是，从单一发源地扩张的模型预测，人口的遗传多样性模式可以很好地通过其从发源地的地理扩张来解释，这与遗传分化有关。
为了在鸡中研究这一点，我们估计了 160 个家养鸡群的遗传多样性与其与野生鸡群的遗传距离之间的关系。
我们的结果显示出强烈的反比关系，即家养鸡群的整体遗传多样性的 88.6%可以用其与野生种群的遗传距离来解释。我们还研究了不同类型的单核苷酸多态性（SNP）和基因的遗传多样性模式是否与整个基因组相似。在 SNP 类别中，非同义 SNP 与整个基因组的偏差最大。然而，与野生鸡的遗传距离仍然解释了不同 SNP 类别中家养鸡多样性的更多变化，范围从 83.0%到 89.3%。
家养鸡群与其野生亲缘之间的遗传距离可以预测家养鸡群的遗传多样性。一方面，无论与野生种群的遗传距离如何，在种群之间遗传变异较小的基因都与大脑发育等主要功能有关。这些基因的变化可能对物种有害。另一方面，与蛋白质运输和蛋白质及脂质代谢过程等相关的基因，其遗传多样性似乎在基因内以更快的速度变化。一般来说，这些基因可能根据种群的需要而具有灵活性。这些结果有助于了解鸡中不同功能基因组区域的进化模式。
