title: Identification and evolution of the orphan genes in the domestic silkworm, Bombyx mori.
abstract: Orphan genes (OGs) which have no recognizable homology to any sequences in other species could contribute to the species specific adaptations. In this study, we identified 738 OGs in the silkworm genome. About 31% of the silkworm OGs is derived from transposable elements, and 5.1% of the silkworm OGs emerged from gene duplication followed by divergence of paralogs. Five de novo silkworm OGs originated from non-coding regions. Microarray data suggested that most of the silkworm OGs were expressed in limited tissues. RNA interference experiments suggested that five de novo OGs are not essential to the silkworm, implying that they may contribute to genetic redundancy or species-specific adaptation. Our results provide some new insights into the evolutionary significance of the silkworm OGs.
authors: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China.
authors: Wei
authors: W
authors: Sun
authors: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China.
authors: Xin-Wei
authors: XW
authors: Zhao
authors: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 400044, China. Electronic address: zezhang@cqu.edu.cn.
authors: Ze
authors: Z
authors: Zhang
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics* / Q000254:growth & development; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D017344:Genes, Insect / Q000235:genetics*; D010802:Phylogeny
keywords: Evolution; Expression; Orphan gene; Silkworm