Microsatellite variation among divergent populations of stalk-eyed flies, genus Cyrtodiopsis.
Microsatellite variation among divergent populations of stalk-eyed flies, genus Cyrtodiopsis.
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茎眼蝇属不同种群之间的微卫星变异。
DOI：
10.1017/s0016672304006986
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
Wilkinson,GeraldS
中科院分区：
文献类型：
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作者：
Wright,TimothyF;Johns,PhilipM;Walters,JamesR;Lerner,AdamP;Swallow,JohnG;Wilkinson,GeraldS
微卫星引物通常在一个物种中开发，并用于评估相关物种的中性变异。这种分析可能因确定偏差（即随着与微卫星源的遗传距离增加，扩增成功率和等位基因变异性下降）而受到干扰。此外，其他因素，如微卫星的大小，它是由完美的还是中断的串联重复序列组成，以及它是常染色体还是x连锁，都可以影响变异。为了测试这些因素对微卫星变异的相对重要性，我们研究了从6个胞藻柄眼蝇群体中每个群体的5个个体中扩增出的52个微卫星位点的扩增模式和等位基因多样性，这些位点与用于微卫星发育的群体的线粒体DNA序列差异在2.2%至11.2%之间。我们发现扩增成功率和大多数等位基因多样性随与源群体的遗传距离而下降，在某些情况下比鸟类或哺乳动物快一个数量级。重复序列长度的中位数和范围不随遗传距离的增加而减小。此外，对于X染色体上的位点，我们发现与常染色体上的位点相比，观察到的杂合性较低。染色体有效种群大小的差异不能充分解释x连锁位点和常染色体位点之间的变异性差异。相反，我们认为，与x染色体减数分裂驱动相关的周期性选择事件（存在于许多这些种群中）减少了x连锁变异。
Microsatellite primers are often developed in one species and used to assess neutral variability in related species. Such analyses may be confounded by ascertainment bias (i.e. a decline in amplification success and allelic variability with increasing genetic distance from the source of the microsatellites). In addition, other factors, such as the size of the microsatellite, whether it consists of perfect or interrupted tandem repeats, and whether it is autosomal or X-linked, can affect variation. To test the relative importance of these factors on microsatellite variation, we examine patterns of amplification and allelic diversity in 52 microsatellite loci amplified from five individuals in each of six populations of Cyrtodiopsis stalk-eyed flies that range from 2·2% to 11·2% mitochondrial DNA sequence divergence from the population used for microsatellite development. We find that amplification success and most measures of allelic diversity declined with genetic distance from the source population, in some cases an order of magnitude faster than in birds or mammals. The median and range of the repeat array length did not decline with genetic distance. In addition, for loci on the X chromosome, we find evidence of lower observed heterozygosity compared with loci on autosomes. The differences in variability between X-linked and autosomal loci are not adequately explained by differences in effective population sizes of the chromosomes. We suggest, instead, that periodic selection events associated with X-chromosome meiotic drive, which is present in many of these populations, reduces X-linked variation.