Primmer C R, Møller A P, Ellegren H
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Mol Ecol. 1996 Jun;5(3):365-78. doi: 10.1111/j.1365-294x.1996.tb00327.x.
The possibility to perform cross-species microsatellite amplification in birds was surveyed by analysing sets of primers developed from the swallow and the pied flycatcher genomes on a panel of 48 different bird species. In total, 162 cases (species/marker combinations) of heterologous amplification were recorded. Ten amplification products were sequenced and all were found to be true homologues of the original loci. There was a significant and negative relationship between microsatellite performance and evolutionary distance between the original species and the tested species. As a rough indicator of expected cross-species microsatellite performance we estimate that 50% of markers will reveal polymorphism in a species with a DNA-DNA hybridization delta T(m)H value of 5 separating it from the original species. This corresponds to a divergence time of = 11 million years before present for passerine birds. The established relationship between performance and evolutionary distance agrees very well with data obtained from some mammalian species. The proportion of polymorphic loci among those markers that amplified decreased with increasing genetic distance, suggesting that few long repeats are preserved during evolution. One of the swallow markers, HrU2, amplified a specific product in all species analyzed and will thus allow access of nuclear sequence data over a broad range of species. The only predictor of cross-species performance was the amount of non-specific amplification seen in the original species. An analysis of 10 species from within the family Hirundinidae with the swallow primers consistently revealed extensive polymorphism with average probabilities of identical genotypes ranging from 6 x 10(-4) to 6 x 10(-7). There were distinct allele frequency differences between the Hirundinidae species and we envisage that microsatellite cross-species amplification will be a useful tool in phylogeny construction and in species identification.
通过分析从家燕和斑姬鹟基因组开发的引物组，在48种不同鸟类组成的样本上调查了鸟类中进行跨物种微卫星扩增的可能性。总共记录了162例（物种/标记组合）异源扩增情况。对10个扩增产物进行了测序，发现它们都是原始位点的真正同源物。微卫星性能与原始物种和测试物种之间的进化距离呈显著负相关。作为预期跨物种微卫星性能的粗略指标，我们估计，对于与原始物种DNA-DNA杂交ΔT(m)H值为5的物种，50%的标记将显示多态性。这对应于雀形目鸟类距今约1100万年的分歧时间。性能与进化距离之间建立的关系与从一些哺乳动物物种获得的数据非常吻合。随着遗传距离增加，扩增的标记中多态位点的比例降低，这表明在进化过程中很少有长重复序列得以保留。家燕的一个标记HrU2在所有分析的物种中都扩增出一个特异性产物，因此将有助于获取广泛物种的核序列数据。跨物种性能的唯一预测指标是原始物种中观察到的非特异性扩增量。用家燕引物对燕科内的10个物种进行分析，始终显示出广泛的多态性，相同基因型的平均概率范围从6×10⁻⁴到6×10⁻⁷。燕科物种之间存在明显的等位基因频率差异，我们设想微卫星跨物种扩增将成为系统发育构建和物种鉴定的有用工具。
