The Anolis lizard genome: an amniote genome without isochores.
The Anolis lizard genome: an amniote genome without isochores.
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DOI：
10.1093/gbe/evr072
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发表时间：
2011
影响因子：
3.3
通讯作者：
Ponting CP
中科院分区：
文献类型：
--
作者：
Fujita MK;Edwards SV;Ponting CP
同工是核苷酸组成相对均匀的大区域，存在于迄今已测序的所有哺乳动物和鸟类的基因组中。新测序的carolinensis基因组提供了第一个机会来量化非鸟类爬行动物的等差结构。我们发现Anolis具有迄今为止所有羊膜动物测序中最均匀的基因组，其均匀性超过了非洲爪蟾。基于贝叶斯算法，与人类和鸡相比，Anolis具有更小且更少的GC-rich等杂项。通常与富含gc的同工相关联的相关基因，包括较短的内含子和较高的基因密度，几乎都从Anolis基因组中消失了。利用基因GC作为等差结构的代表，与其他脊椎动物进行比较，我们发现从爬行动物的共同祖先分化到Anolis的谱系中，GC含量大幅减少，可能反映了GC偏向的基因转换减弱或逆转，这是一种非适应性替代过程，被认为在等差进化的维持和轨迹中很重要。我们的研究结果表明，与哺乳动物和鸟类基因组的模式相反，Anolis的GC组成与基因组结构的重要特征（包括基因密度和内含子大小）无关。
Isochores are large regions of relatively homogeneous nucleotide composition and are present in the genomes of all mammals and birds that have been sequenced to date. The newly sequenced genome of Anolis carolinensis provides the first opportunity to quantify isochore structure in a nonavian reptile. We find Anolis to have the most compositionally homogeneous genome of all amniotes sequenced thus far, a homogeneity exceeding that for the frog Xenopus. Based on a Bayesian algorithm, Anolis has smaller and less GC-rich isochores compared with human and chicken. Correlates generally associated with GC-rich isochores, including shorter introns and higher gene density, have all but disappeared from the Anolis genome. Using genic GC as a proxy for isochore structure so as to compare with other vertebrates, we found that GC content has substantially decreased in the lineage leading to Anolis since diverging from the common ancestor of Reptilia ∼275 Ma, perhaps reflecting weakened or reversed GC-biased gene conversion, a nonadaptive substitution process that is thought to be important in the maintenance and trajectory of isochore evolution. Our results demonstrate that GC composition in Anolis is not associated with important features of genome structure, including gene density and intron size, in contrast to patterns seen in mammal and bird genomes.
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影响因子：
3.9
作者：
BERNARDI, G;BERNARDI, G
通讯作者：
BERNARDI, G
影响因子：
3.9
作者：
Belle, EMS;Smith, N;Eyre-Walker, A
通讯作者：
Eyre-Walker, A
影响因子：
7
作者：
Costantini, M;Clay, O;Bernardi, G
通讯作者：
Bernardi, G
影响因子：
64.5
作者：
BROWN, TC;JIRICNY, J
通讯作者：
JIRICNY, J
影响因子：
3.9
作者：
DURET, L;MOUCHIROUD, D;GAUTIER, C
通讯作者：
GAUTIER, C