Division of Radiological Protection and Biology, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan.
Genetics. 2011 Mar;187(3):965-76. doi: 10.1534/genetics.110.124982. Epub 2011 Jan 17.
The carotenoid-binding protein (CBP) of the domesticated silkworm, Bombyx mori, a major determinant of cocoon color, is likely to have been substantially influenced by domestication of this species. We analyzed the structure of the CBP gene in multiple strains of B. mori, in multiple individuals of the wild silkworm, B. mandarina (the putative wild ancestor of B. mori), and in a number of other lepidopterans. We found the CBP gene copy number in genomic DNA to vary widely among B. mori strains, ranging from 1 to 20. The copies of CBP are of several types, based on the presence of a retrotransposon or partial deletion of the coding sequence. In contrast to B. mori, B. mandarina was found to possess a single copy of CBP without the retrotransposon insertion, regardless of habitat. Several other lepidopterans were found to contain sequences homologous to CBP, revealing that this gene is evolutionarily conserved in the lepidopteran lineage. Thus, domestication can generate significant diversity of gene copy number and structure over a relatively short evolutionary time.
家蚕的类胡萝卜素结合蛋白（CBP）是茧色的主要决定因素，它很可能受到该物种驯化的强烈影响。我们分析了多个家蚕品系、野生蚕（家蚕的假定野生祖先 B. mandarina）多个个体以及一些其他鳞翅目昆虫的 CBP 基因结构。我们发现，家蚕品系之间的 CBP 基因拷贝数在基因组 DNA 中差异很大，范围从 1 到 20。根据逆转录转座子的存在或编码序列的部分缺失，CBP 的拷贝数有几种类型。与家蚕不同的是，无论栖息地如何，我们发现 B. mandarina 只含有一个没有逆转录转座子插入的 CBP 拷贝。其他几种鳞翅目昆虫被发现含有与 CBP 同源的序列，这表明该基因在鳞翅目谱系中具有进化保守性。因此，在相对较短的进化时间内，驯化可以产生基因拷贝数和结构的显著多样性。
