Highly conserved linkage homology between birds and turtles: Bird and turtle chromosomes are precise counterparts of each other
Highly conserved linkage homology between birds and turtles: Bird and turtle chromosomes are precise counterparts of each other
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DOI：
10.1007/s10577-005-0986-5
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发表时间：
2005-08-01
影响因子：
2.6
通讯作者：
Agata, K
中科院分区：
文献类型：
--
作者：
Matsuda, Y;Nishida-Umehara, C;Agata, K
鸟、龟和蛇的核型有两种不同的染色体组成，即大染色体和微染色体。鸟类和爬行动物之间这种密切的核生物学关系一直是细胞遗传学家和进化生物学家猜测的话题；然而，几乎没有任何证据表明在分子水平上存在同源性。为了确定人、鸡和爬行动物之间的保守染色体合群以及羊膜动物的基因组进化过程，我们利用爬行动物功能基因的cDNA克隆构建了中国软壳龟（Pelodiscus sinensis）和日本四条纹鼠蛇（Elaphe quadrivirgata）的细胞遗传学比较图谱。龟和鸡染色体的同源性是高度保守的，最大的六条染色体几乎是相等的。另一方面，蛇与鸡染色体的同源性低于龟。龟的6q染色体和蛇的2p染色体与鸡的Z染色体具有保守的同源性。这些结果表明，鸟和龟的基因组在Arcosauria的进化过程中得到了很好的保存。鸟类和蛇的性Z染色体来源于同一祖先的不同常染色体，表明鸟类和蛇的性别决定的致病基因可能不同。
The karyotypes of birds, turtles and snakes are characterized by two distinct chromosomal components, macrochromosomes and microchromosomes. This close karyological relationship between birds and reptiles has long been a topic of speculation among cytogeneticists and evolutionary biologists; however, there is scarcely any evidence for orthology at the molecular level. To define the conserved chromosome synteny among humans, chickens and reptiles and the process of genome evolution in the amniotes, we constructed comparative cytogenetic maps of the Chinese soft-shelled turtle (Pelodiscus sinensis) and the Japanese four-striped rat snake (Elaphe quadrivirgata) using cDNA clones of reptile functional genes. Homology between the turtle and chicken chromosomes is highly conserved, with the six largest chromosomes being almost equivalent to each other. On the other hand, homology to chicken chromosomes is lower in the snake than in the turtle. Turtle chromosome 6q and snake chromosome 2p represent conserved synteny with the chicken Z chromosome. These results suggest that the avian and turtle genomes have been well conserved during the evolution of the Arcosauria. The avian and snake sex Z chromosomes were derived from different autosomes in a common ancestor, indicating that the causative genes of sex determination may be different between birds and snakes.