Gene duplication plays a major role in gene co-option: Studies into the evolution of the motilin/ghrelin family and their receptors  

作　　者：HE Jing Irwin M. DAVID ZHANG YaPing 

机构地区：[1]State Key Laboratory of Genetic Resource and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China [2]Department of Laboratory Medicine and Pathobiology and Banting and Best Diabetes Centre, University of Toronto, Toronto, M5S1A1, Canada [3]Laboratory for Conservation and Utilization ofBioresource, Yunnan University, Kunming 650091, China

出　　处：《Chinese Science Bulletin》2011年第25期2690-2697,共8页

基　　金：supported by the National Basic Research Program of China (2007CB411600);the National Natural Science Foundation of China (30621092,30623007);the Bureau of Science and Technology of Yunnan Province (O803481101)

摘　　要：Extant genes can be modified, or 'tinkered with', to provide new roles or new characteristics of these genes. At the genetic level, this often involves gene duplication and specialization of the resulting genes into particular functions. We investigate how ligand-receptor partnerships evolve after gene duplication. While significant work has been conducted in this area, the examination of additional models should help us better understand the proposed models and potentially reveal novel evolutionary patterns and dynamics. We use bioinformatics, comparative genomics and phylogenetic analyses to show that preproghrelin and prepromotilin descended from a common ancestor and that a gene duplication generated these two genes shortly after the divergence of amphibians and amniotes. The evolutionary history of the receptor family differs from that of their cognate ligands. GPR39 diverges first, and an ancestral receptor gives rise to receptors classified as fish-specific clade A, GHSR and MLNR by successive gene duplications occurring before the divergence of tetrapods and ray-finned fish. The ghrelin/GHSR system is maintained and functionally conserved from fish to mammals. Motilin-MLNR specificity must have arisen by ligand-receptor coevolution after the MLN hormone gene diverged from the GHRL gene in the amniote lineage. Conserved molecular machinery can give rise to new neuroendocrine response mechanisms by the co-option of duplicated genes. Gene duplication is both parsimonious and creative in producing elements for evolutionary tinkering and plays a major role in gene co-option, thus aiding the evolution of greater biological complexity.Extant genes can be modified, or ＇tinkered with＇, to provide new roles or new characteristics of these genes. At the genetic level, this often involves gene duplication and specialization of the resulting genes into particular functions. We investigate how lig-and-receptor partnerships evolve after gene duplication. While significant work has been conducted in this area, the examination of additional models should help us better understand the proposed models and potentially reveal novel evolutionary patterns and dynamics. We use bioinformatics, comparative genomics and phylogenetic analyses to show that preproghrelin and prepromotilin descended from a common ancestor and that a gene duplication generated these two genes shortly after the divergence of amphib- ians and amniotes. The evolutionary history of the receptor family differs from that of their cognate ligands. GPR39 diverges first, and an ancestral receptor gives rise to receptors classified as fish-specific clade A, GHSR and MLNR by successive gene duplica- tions occurring before the divergence of tetrapods and ray-finned fish. The ghrelin/GHSR system is maintained and functionally conserved from fish to mammals. Motilin-MLNR specificity must have arisen by ligand-receptor coevolution after the MLN hormone gene diverged from the GHRL gene in the amniote lineage. Conserved molecular machinery can give rise to new neuro- endocrine response mechanisms by the co-option of duplicated genes. Gene duplication is both parsimonious and creative in pro-ducing elements for evolutionary tinkering and plays a major role in gene co-option, thus aiding the evolution of greater biological complexity.

关 键 词：基因重复 生长素 胃动素 受体 选项 演变 家庭 进化模式 

分 类 号：Q78[生物学—分子生物学]