Molecular population genetics of ref(2)P, a locus which confers viral resistance in Drosophila.
Molecular population genetics of ref(2)P, a locus which confers viral resistance in Drosophila.
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DOI：
10.1093/oxfordjournals.molbev.a025555
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发表时间：
1996
影响因子：
10.7
通讯作者：
Marta L. Wayne;D. Contamine;M. Kreitman
中科院分区：
文献类型：
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作者：
Marta L. Wayne;D. Contamine;M. Kreitman
ref（2）P基因座（2-54.2）在黑腹果蝇自然群体中具有两种等位基因形式（ref（2）Po和ref（2）Pp）的多态性。后一个等位基因赋予对感染野生群体的弹状病毒σ的抗性。先前的工作基于预先筛选的限制性（抗性）和允许性（易感）等位基因的小样本，确定了相对于同义变化（1）的大量氨基酸置换变化（7）。这种蛋白质的变异性可能是变异增强选择的结果。为了进一步验证选择假说，我们检测了十个随机选择的D. melanogaster和D. simulans。10行中有9行是允许的; D。simulans没有携带病毒。黑腹鱼等位基因包含4个同义突变、19个非编码突变和13个氨基酸替换突变，表明其多态性水平较高。三个测序的限制性等位基因具有几乎相同的序列，表明它们相对年轻。与允许等位基因相比，它们仅在密码子34处共享复杂的缺失，CAG-AAT到GGA，我们的分析表明这是赋予限制性表型的位点。多态性和分歧的模式不同于中性预测的几个标准的氨基末端区域，其中包含复杂的缺失（密码子1-91），但不是其余的蛋白质（密码子92-599）。我们发现在D染色体上进化的速度更快。melanogaster谱系上比D. simulans血统允许等位基因中相对大量的替换和沉默多态性以及允许等位基因和限制等位基因之间缺乏分歧表明西格玛病毒和ref（2）P可能参与了一个进化种族，其中新的限制等位基因不断出现，但相对较短。
The ref(2)P locus (2-54.2) is polymorphic for two allelic forms in natural populations of Drosophila melanogaster, ref(2)Po and ref(2)Pp. The latter allele confers resistance to the rhabdovirus sigma infecting wild populations. Previous work, based on a small sample of prescreened restrictive (resistant) and permissive (susceptible) alleles, identified a large number of amino acid replacement changes (7) relative to synonymous changes (1). Such protein variability could be the result of variation-enhancing selection. To further test the selection hypothesis, we have examined the DNA sequences of ten randomly chosen lines of D. melanogaster and one line of D. simulans. Nine of the ten lines are permissive; D. simulans does not harbor the virus. The melanogaster alleles contain 4 synonymous changes, 19 noncoding changes, and 13 amino acid replacement changes, indicating a relatively high level of polymorphism. Three sequenced restrictive alleles have nearly identical sequences, indicating that they are relatively young. Compared to the permissive alleles, they share only a complex deletion at codon 34, CAG-AAT to GGA, which our analysis indicates to be the site conferring the restrictive phenotype. Patterns of polymorphism and divergence differ from neutral predictions by several criteria for the amino terminal region, which contains the complex deletion (codons 1-91), but not the remainder of the protein (codons 92-599). We find a higher rate of evolution on the D. melanogaster lineage than on the D. simulans lineage. The relatively large amount of both replacement and silent polymorphism in the permissive alleles and the lack of divergence between permissive and restrictive alleles suggests that the sigma virus and ref(2)P may be engaged in an evolutionary race in which new restrictive alleles are continually arising but are relatively short-lived.