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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Phylogenomics of nonavian reptiles and the structure of the ancestral amniote genome
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Phylogenomics of nonavian reptiles and the structure of the ancestral amniote genome

机译：非禽类爬行动物的植物学和祖先羊膜基因组的结构

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摘要

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 ≈65,000 8-mer oligonucleotides 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 retro-elements in reptiles that culminated in the minimalist chicken genome.
机译：我们报告了哺乳动物的姊妹群Reptilia的兆碱基规模的系统生物学分析结果。对乌龟，短吻鳄和蜥蜴的基因组克隆进行大规模的末端序列扫描，可以发现在鸡中未发现的多样，类似哺乳动物的反刍元素和简单的序列重复序列（SSR）。几种全球基因组性状，包括CR1样长短穿插元件（LINEs）的独特系统发育谱系和少量富含AT的SSR，可表征乌龟和始祖鸟的基因组，而串联重复的频率较高且整体GC含量较低，则揭示出哺乳动物的特征在Anolis。 Nonavian爬行动物基因组还具有在鸡或哺乳动物中未发现的多种多样且新颖的50 bp单位串联重复频率。 ≈65,000个8-mer寡核苷酸的频率分布表明，爬行动物的DNA词频率变化速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，散布着各种各样的SSR和SSR，而且在极简的鸡基因组中，爬行动物的基因组保守性和逆向元素逐渐丧失。

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