双亲群体中幽灵祖先的存在与丰度。
The existence and abundance of ghost ancestors in biparental populations.
作者信息
Gravel Simon, Steel Mike
机构信息
Genome Quebec Innovation Centre, Department of Human Genetics, McGill University, 740 Dr Penfield, Montreal, Quebec, H3A 0G1, Canada.
Biomathematics Research Centre, University of Canterbury, New Zealand.
出版信息
Theor Popul Biol. 2015 May;101:47-53. doi: 10.1016/j.tpb.2015.02.002. Epub 2015 Feb 19.
In a randomly-mating biparental population of size N there are, with high probability, individuals who are genealogical ancestors of every extant individual within approximately log2(N) generations into the past. We use this result of J. Chang to prove a curious corollary under standard models of recombination: there exist, with high probability, individuals within a constant multiple of log2(N) generations into the past who are simultaneously (i) genealogical ancestors of each of the individuals at the present, and (ii) genetic ancestors to none of the individuals at the present. Such ancestral individuals-ancestors of everyone today that left no genetic trace-represent 'ghost' ancestors in a strong sense. In this short note, we use simple analytical argument and simulations to estimate how many such individuals exist in finite Wright-Fisher populations.
在一个大小为(N)的随机交配双亲群体中，很有可能存在这样的个体，它们是过去大约(\log_2(N))代内每个现存个体的谱系祖先。我们利用J. 张的这一结果，在标准重组模型下证明了一个奇特的推论：很有可能在过去(\log_2(N))的常数倍代内存在这样的个体，它们同时满足：(i) 是当前每个个体的谱系祖先；(ii) 不是当前任何个体的基因祖先。这种祖先个体——现今所有人的祖先却没有留下基因痕迹——在很强的意义上代表了“幽灵”祖先。在本简短笔记中，我们使用简单的分析论证和模拟来估计在有限的赖特 - 费希尔群体中存在多少这样的个体。
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