Phylogenomics of nonavian reptiles and the structure of the ancestral amniote genorne
Phylogenomics of nonavian reptiles and the structure of the ancestral amniote genorne
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DOI：
10.1073/pnas.0606204104
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发表时间：
2007-02-20
影响因子：
11.1
通讯作者：
Edward, Scott V.
中科院分区：
文献类型：
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作者：
Shedlock, Andrew M.;Botka, Christopher W.;Edward, Scott V.
我们报告了哺乳动物姐妹组爬行动物的大型系统基因组分析结果。对海龟、鳄鱼和蜥蜴的基因组克隆进行大规模的末端序列扫描，揭示了在鸡中没有发现的不同的、类似哺乳动物的逆转录因子和简单序列重复（SSRs）。龟类和始祖龙的基因组具有一些全球基因组特征，包括cr1样长穿插元件（LINEs）的独特系统发育谱系和富含a - t的SSRs的缺乏，而龟类基因组具有较高的串联重复频率和较低的全球GC含量，显示出类似哺乳动物的特征。非鸟类爬行动物基因组还具有鸡或哺乳动物中未发现的多种新颖的50 bp单位串联重复。大约65,000个8-聚寡核苷酸的频率分布表明，爬行动物的dna词频变化率比哺乳动物慢一个数量级。这些结果表明，在羊膜动物的共同祖先中存在多种分散的和ssr，爬行动物的基因组保守性和逆转录因子的逐渐丧失最终导致了极简主义的鸡基因组。
We report results of a megabase-scale phylogenomic analysis of the Reptilia, the sister group of mammals. Large-scale end-sequence scanning of genomic clones of a turtle, alligator, and lizard reveals diverse, mammal-like landscapes of retroelements and simple sequence repeats (SSRs) not found in the chicken. Several global genomic traits, including distinctive phylogenetic lineages of CR1-like long interspersed elements (LINEs) and a paucity of A-T rich SSRs, characterize turtles and archosaur genomes, whereas higher frequencies of tandem repeats and a lower global GC content reveal mammal-like features in Anolis. Nonavian reptile genomes also possess a high frequency of diverse and novel 50-bp unit tandem duplications not found in chicken or mammals. The frequency distributions of approximate to 65,000 8-meroligonucleotides suggest that rates of DNA-word frequency change are an order of magnitude slower in reptiles than in mammals. These results suggest a diverse array of interspersed and SSRs in the common ancestor of amniotes and a genomic conservatism and gradual loss of retroelements in reptiles that culminated in the minimalist chicken genome.