Estimators of the Human Effective Sex Ratio Detect Sex Biases on Different Timescales
Estimators of the Human Effective Sex Ratio Detect Sex Biases on Different Timescales
复制标题
DOI：
10.1016/j.ajhg.2010.10.021
复制
发表时间：
2010-12-10
影响因子：
9.8
通讯作者：
Akey, Joshua M.
中科院分区：
文献类型：
--
作者：
Emery, Leslie S.;Felsenstein, Joseph;Akey, Joshua M.
确定整个人类进化过程中的历史性别比例可以深入了解基因组变异的模式，古代人口的结构和组成，以及影响性别比例的文化因素（例如，按性别分列的移徙率）。虽然许多研究表明，在人类进化史上存在性别比例不平等，但性别偏见过程的连贯画面尚未出现。例如，最近的两项研究将人类X染色体与常染色体变异进行了比较，以推断历史性别比例，但得出了看似矛盾的结论，其中一项研究发现了男性偏见的证据，另一项研究则确定了女性偏见。在这里，我们表明，这种差异的很大一部分可以解释方法的差异。具体而言，通过重新分析的经验数据，推导明确的分析公式，并进行了广泛的模拟，我们证明了两个估计的有效性别比的基础上人口结构和核苷酸多样性优先检测偏差，发生在不同的时间尺度。我们的研究结果澄清了明显矛盾的证据性别偏见的过程中的作用，在人类进化史上，并表明，人类基因组变异的现存模式是一致的，最近的男性偏见和早期，持续的女性偏见。
Determining historical sex ratios throughout human evolution can provide insight into patterns of genomic variation, the structure and composition of ancient populations, and the cultural factors that influence the sex ratio (e.g., sex-specific migration rates). Although numerous studies have suggested that unequal sex ratios have existed in human evolutionary history, a coherent picture of sex-biased processes has yet to emerge. For example, two recent studies compared human X chromosome to autosomal variation to make inferences about historical sex ratios but reached seemingly contradictory conclusions, with one study finding evidence for a male bias and the other study identifying a female bias. Here, we show that a large part of this discrepancy can be explained by methodological differences. Specifically, through reanalysis of empirical data, derivation of explicit analytical formulae, and extensive simulations we demonstrate that two estimators of the effective sex ratio based on population structure and nucleotide diversity preferentially detect biases that have occurred on different timescales. Our results clarify apparently contradictory evidence on the role of sex-biased processes in human evolutionary history and show that extant patterns of human genomic variation are consistent with both a recent male bias and an earlier, persistent female bias.