Intraspecific DNA variation in nuclear genes of the mosquito Aedes aegypti
Intraspecific DNA variation in nuclear genes of the mosquito Aedes aegypti
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DOI：
10.1046/j.1365-2583.2003.00449.x
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发表时间：
2003-12-01
影响因子：
2.6
通讯作者：
Severson, DW
中科院分区：
文献类型：
--
作者：
Morlais, I;Severson, DW
单核苷酸多态性 (SNP) 是个体生物体遗传变异的丰富来源。为了评估 SNP 在黄热病蚊子（埃及伊蚊）基因组分析中的有用性，我们对三个品系中每一个品系的 25 个核基因进行了测序，并分析了核苷酸多样性。核苷酸变异的平均频率为每千碱基 12 个 SNP，表明 Ae 中的核苷酸变异。埃及伊蚊与其他生物体相似，包括果蝇和疟疾媒介冈比亚按蚊。转换多态性的数量多于颠换多态性，比例约为 2:1。我们检查了密码子的使用并证实突变偏向有利于 G 和 C 结尾密码子。密码子偏倚在高表达基因中最为明显。核苷酸多样性估计表明编码区和非编码区的取代率呈正相关。一个基因与另一个基因之间的核苷酸多样性有所不同。 Ae 中 SNP 的分布不均。埃及伊核基因表明单碱基变异是非中性的并且受到选择性限制。我们的分析表明，普遍表达的基因具有较低的多态性率，并且可能处于强纯化选择下，而组织特异性基因和在寄生虫防御中具有推定作用的基因表现出较高水平的多态性，这可能与多样化选择有关。
Single nucleotide polymorphisms (SNPs) are an abundant source of genetic variation among individual organisms. To assess the usefulness of SNPs for genome analysis in the yellow fever mosquito, Aedes aegypti, we sequenced 25 nuclear genes in each of three strains and analysed nucleotide diversity. The average frequency of nucleotide variation was 12 SNPs per kilobase, indicating that nucleotide variation in Ae. aegypti is similar to that in other organisms, including Drosophila and the malaria vector Anopheles gambiae. Transition polymorphisms outnumbered transversion polymorphisms, at a ratio of about 2 : 1. We examined codon usage and confirmed that mutational bias favours G and C ending codons. Codon bias was most pronounced in highly expressed genes. Nucleotide diversity estimates indicated that substitution rates are positively correlated in coding and non-coding regions. Nucleotide diversity varied from one gene to another. The unequal distribution of SNPs among Ae. aegypti nuclear genes suggests that single base variations are non-neutral and are subject to selective constraints. Our analysis showed that ubiquitously expressed genes have lower polymorphism rates and are likely under strong purifying selection, whereas tissue specific genes and genes with a putative role in parasite defence exhibit higher levels of polymorphism that may be associated with diversifying selection.