野桑蚕性信息素结合蛋白基因pbp1、气味受体基因or1和or3的克隆及其与家蚕同源基因的进化分析

昆虫能够特异性识别同类异性。雄蚕蛾对雌蚕蛾感知定位过程中, 性信息素结合蛋白PBP1、气味受体OR1和OR3起重要作用。为研究家蚕Bombyx mori和野桑蚕Bombyx mandarina杂交困难的分子机制, 了解性识别相关基因的进化, 本研究克隆得到了野桑蚕的性信息素结合蛋白基因pbp1（GenBank注册号：GQ246497）和气味受体基因or1（Genank注册号：GQ246496）和or3（GenBank注册号：GQ246498）。序列分析发现, 家蚕与野桑蚕相比, pbp1基因存在4个SNP位点, 分别为C10A, A40T, T270C和A333G, 其中2个SNP位点引起氨基酸的改变, 分别为Q→K和N→Y; or1基因存在5个SNP位点, 分别为T910C, A1147C, A1192T, T1276C和G1282A, 其中1个SNP位点引起氨基酸F→L的改变; or3基因存在4个SNP位点, 分别为A507G, A513G, T605C和G672A, 其中1个SNP位点引起氨基酸I→T的改变。3个基因的遗传距离很近, 进化速率也很慢。氨基酸的分子量和等电点有细微差异或无差异。PHD预测的二级结构表明, 变异位点对附近区域的结构没有任何影响, 功能位点也没有变化。推测家蚕与野桑蚕之间, 这些基因功能可能没有差异, 即二者的雌雄性个体间可以相互感知、识别, 这与实验观察结果一致。

Cloning of pbp1, or1 and or3 from wild silkworm Bombyx mandarina and evolutional analysis with the orthologous genes of domesticated silkworm Bombyx mori

Insects can specially recognize the opposite sexes of the same species. PBP1, OR1 and OR3 play an important role in the process of the male silkworm Bombyx mori perception and location of the females. For the purpose of finding out the molecular mechanism of difficult hybridization of B. mori and B. mandarina, and understanding the evolution of related genes to sexual recognition between the two species, we cloned three genes (Bmmpbp1, GenBank ID: GQ246497; Bmmor1, GenBank ID: GQ246496; Bmmor3, GenBank ID: GQ246498) of wild silkworm B. mandarina. Sequences analysis revealed that between the two species there were 4 single nucleotide polymorphisims (SNPs) (C10A, A40T, T270C and A333G) in pbp1, two of which caused amino acid variation (Q to K, N to Y); there were 5 SNPs (T910C, A1147C, A1192T, T1276C and G1282A) in or1 and only 1 induced amino acid variation (F to L), and there were 4 SNPs (A507G, A513G, T605C and G672A) in or3 and 1 caused amino acid mutation (I to T). The genetic distances of the three genes are close and the evolution velocities are low. Secondary structure predicted by PHD program on line suggested that mutation sites had no influence on the adjoining regions, or on the functional sites. There are presumably no functional differences in these genes of the two related moths. Namely, male and female individuals could perceive and recognize mutually between the two species. Our findings were consistent with the experimental observations.