Microsatellite evolution at two hypervariable loci revealed by extensive avian pedigrees
Microsatellite evolution at two hypervariable loci revealed by extensive avian pedigrees
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DOI：
10.1093/molbev/msg005
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发表时间：
2003-01-01
影响因子：
10.7
通讯作者：
Cockburn, A
中科院分区：
文献类型：
--
作者：
Beck, NR;Double, MC;Cockburn, A
利用长期研究产生的家系，研究了两个高变数的微卫星座位内的突变情况。在检测到的3230个四核苷酸座位(Mcymu8)的减数分裂中，发现了45个突变，突变率为1.4%。在二核苷酸基因座(Mcymu4)，2750个减数分裂中记录到30个突变，突变率为1.1%。两个基因座的突变主要涉及单个重复单位的丢失或获得(80%；60/75)。与之前的研究不同，没有明显的偏向于增加而不是删除。Mcymu8的突变率随着等位基因大小的增加而增加，超长等位基因(>；70重复)的突变率接近20%。然而，突变等位基因的长度和等位基因跨度之间存在很强的相关性，因此不可能分离出致病因子。等位基因大小似乎不影响Mcymu4的突变率，但该基因座的重复数明显较低。突变亲本的性别仅在Mcymu8显著，母系等位基因发生突变的频率更高。然而，在这两个基因座上，我们发现母亲遗传的等位基因平均比父亲遗传的等位基因大，这在一定程度上导致了Mcymu8的母亲遗传等位基因中更高的突变率。
Genealogies generated through a long-term study of superb fairy-wrens (Malurus cyaneus) were used to investigate mutation, within two hypervariable microsatellite loci. Of 3,230 meioses examined at the tetranucleotide locus (Mcymu8), 45 mutations were identified, giving a mutation rate of 1.4%. At the dinucleotide locus (Mcymu4) 30 mutations were recorded from 2,750 meioses giving a mutation rate of 1.1%. Mutations at both loci primarily (80%; 60/75) involved the loss or gain of a single repeat unit. Unlike previous studies, there was no significant bias toward additions over deletions. The mutation rate at Mcymu8 increased with allele size, and very long alleles (>70 repeats) mutated at a rate of almost 20%. The length of the mutating allele and allele span, however, were strongly correlated so it was not possible to isolate the causative factor. Allele size did not appear to affect mutation rate at Mcymu4, but the repeat number was considerably lower at this locus. The gender of the mutating parent was significant only at Mcymu8, where mutations occurred more frequently in maternal alleles. However, at both loci we found that alleles inherited from the mother were on average larger than those from the father, and this in part drove the higher mutation rate among maternally inherited alleles at Mcymu8.