Cooper G, Amos W, Hoffman D, Rubinsztein D C
University of Cambridge, Department of Genetics, UK.
Hum Mol Genet. 1996 Nov;5(11):1759-66. doi: 10.1093/hmg/5.11.1759.
To investigate the utility of Y chromosome microsatellites for studying human male-lineage evolution, we typed samples from three populations for five tetranucleotide repeats and an Alu insertion polymorphism. We found very high levels of haplotype diversity and evidence that most mutations involve the gain or loss of only one repeat unit, implying that any given microsatellite haplotype may have arisen independently on two or more Y-chromosome lineages. Together, these factors suggest that interpretation of small sample sizes (< 30) will be problematic. By typing a large sample of individuals (n = 174) from one population, East Anglia, we were able to construct a haplotype network. The network exhibits a well-connected core structure of commoner haplotypes. Computer simulations based on this network estimate the convergence time for African and Caucasian groups may be between 1.4 and 1.8 times as long as the convergence of the East Anglian population. Based on our comparison between large and small sample sizes, we suggest that large sample sizes are necessary in order to interpret Y-microsatellite haplotypes, and that a network analysis of the type we describe may prove informative in future studies.
为了研究Y染色体微卫星在人类父系谱系进化研究中的效用，我们对来自三个群体的样本进行了五个四核苷酸重复序列和一个Alu插入多态性的分型。我们发现单倍型多样性水平非常高，且有证据表明大多数突变仅涉及一个重复单元的增减，这意味着任何给定的微卫星单倍型可能在两个或更多Y染色体谱系上独立出现。这些因素共同表明，对小样本量（<30）的解读会存在问题。通过对来自东安格利亚一个群体的大量个体（n = 174）进行分型，我们得以构建一个单倍型网络。该网络呈现出一个由较常见单倍型构成的连接良好的核心结构。基于此网络的计算机模拟估计，非洲和高加索群体的趋同时间可能是东安格利亚群体趋同时间的1.4至1.8倍。基于我们对大样本量和小样本量的比较，我们认为需要大样本量才能解读Y微卫星单倍型，并且我们所描述的这种类型的网络分析在未来研究中可能会被证明是有价值的。
