Rapid evolution of smell and taste receptor genes during host specialization in Drosophila sechellia
Rapid evolution of smell and taste receptor genes during host specialization in Drosophila sechellia
复制标题
DOI：
10.1073/pnas.0608424104
复制
发表时间：
2007-03-20
影响因子：
11.1
通讯作者：
McBride, Carolyn S.
中科院分区：
文献类型：
--
作者：
McBride, Carolyn S.
我们对昆虫宿主特化的遗传基础的理解仅限于有关显着表型变化的遗传因素的数量和位置的基本信息。我们对可能伴随宿主特化的分子进化的一般模式一无所知，但无法追溯到单个显着的表型变化。在这里，我描述了最近特化的醋蝇 Drosophila sechellia 的 136 个嗅觉受体 (Or) 和味觉受体 (Gr) 基因的全部变化。我发现 D. sechellia 失去 Or 和 Gr 基因的速度比它的多面手同胞果蝇快近 10 倍。此外，那些保持完整的 D. sechellia 受体比其 D. simulans 直系同源物具有相对于沉默突变更高的固定氨基酸置换突变率。将这些模式与随机基因样本中观察到的模式进行比较表明，Or 和 Gr 基因座的变化可能反映了与该果蝇生态位改变相关的积极选择和/或放松约束。
Our understanding of the genetic basis of host specialization in insects is limited to basic information on the number and location of genetic factors underlying changes in conspicuous phenotypes. We know nothing about general patterns of molecular evolution that may accompany host specialization but are not traceable to a single prominent phenotypic change. Here, I describe changes in the entire repertoire of 136 olfactory receptor (Or) and gustatory receptor (Gr) genes of the recently specialized vinegar fly Drosophila sechellia. I find that D. sechellia is losing Or and Gr genes nearly 10 times faster than its generalist sibling Drosophila simulans. Moreover, those D. sechellia receptors that remain intact have fixed amino acid replacement mutations at a higher rate relative to silent mutations than have their D. simulans orthologs. Comparison of these patterns with those observed in a random sample of genes indicates that the changes at Or and Gr loci are likely to reflect positive selection and/or relaxed constraint associated with the altered ecological niche of this fly.