tailieunhanh - Báo cáo sinh học: "Comparing the retention mechanisms of tandem duplicates and retrogenes in human and mouse genomes"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học quốc tế đề tài: Comparing the retention mechanisms of tandem duplicates and retrogenes in human and mouse genomes | Wang et al. Genetics Selection Evolution 2010 42 24 http content 42 1 24 Ge n et i cs Selection Evolution RESEARCH Open Access Comparing the retention mechanisms of tandem duplicates and retrogenes in human and mouse genomes Zhen Wang 1 2 Xiao Dong1 2 Guohui Ding 1 3 and Yixue Li 1 3 Abstract Background Multiple models have been proposed to interpret the retention of duplicated genes. In this study we attempted to compare whether the duplicates arising from tandem duplications and retropositions are retained by the same mechanisms in human and mouse genomes. Results Both sequence and expression similarity analyses revealed that tandem duplicates tend to be more conserved whereas retrogenes tend to be more divergent. The duplicability of tandem duplicates is also higher than that of retrogenes. However positive selection seems to play significant roles in the retention of both types of duplicates. Conclusions We propose that dosage effect is more prevalent in the retention of tandem duplicates while escape from adaptive conflict EAC effect is more prevalent in the retention of retrogenes. Background Gene duplication is one of the most important sources of genomic novelty and complexity 1 . There are three main molecular mechanisms leading to new duplicates 2 3 1 unequal crossing-over during homologous recombination 2 duplicative transposition at the DNA level and retroposition mediated by mRNA and 3 poly-ploidization. While polyploidization is characterized by bursts of large-scale genome duplication the former two processes are often small-scale and proceed continuously 4 . Recently the investigations of full genome sequences have revealed that both large- and small-scale duplications play significant roles in the evolution of various organisms 5 . Although the molecular basis of gene duplication has been well understood how the newly created duplicates are fixed in the population is still quite controversial 6 . Several evolutionary models for .