Zebrafish comparative genomics and the origins of vertebrate chromosomes
Zebrafish comparative genomics and the origins of vertebrate chromosomes
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DOI：
10.1101/gr.164800
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发表时间：
2000-12-01
期刊：
影响因子：
7
通讯作者：
Talbot, WS
中科院分区：
文献类型：
--
作者：
Postlethwait, JH;Woods, IG;Talbot, WS
为了帮助理解脊椎动物基因组进化的机制，我们比较了斑马鱼和四足动物的基因图谱。有人认为，在哺乳动物中，易位比倒位更频繁地被固定。基因图谱显示，斑马鱼和人类之间的保守同线性块很大，但基因顺序经常倒置和转置。这表明染色体内重排比易位更频繁地被固定。重复的染色体片段表明，射线鳍系统发育中发生了基因组重复，而比较研究表明，这一事件发生在硬骨鱼祖先的深处。对重复染色体片段的考虑表明，至少 20% 的重复基因对可能从此事件中保留下来。尽管存在基因组重复，但斑马鱼和人类的染色体数量大致相同，并且斑马鱼染色体与几条人类染色体是嵌合直系同源的。这是因为人类谱系中染色体裂变过多还是斑马鱼谱系中染色体融合过多？比较分析表明，四足动物谱系中过量的染色体裂变可能是染色体数量的原因，并提供了几种人类染色体的历史。
To help understand mechanisms of vertebrate genome evolution we have compared zebrafish and tetrapod gene maps. It has been suggested that translocations are fixed more frequently than inversions in mammals. Gene maps showed that blocks of conserved syntenies between zebrafish and humans were large, but gene orders were frequently inverted and transposed. This shows that intrachromosomal rearrangements have been fixed more frequently than translocations. Duplicated chromosome segments suggest that a genome duplication occurred in ray-fin phylogeny, and comparative studies suggest that this event happened deep in the ancestry of teleost fish. Consideration of duplicate chromosome segments shows that at least 20% of duplicated gene pairs may be retained from this event. Despite genome duplication, zebrafish and humans have about the same number of chromosomes, and zebrafish chromosomes are mosaically orthologous to several human chromosomes. Is this because of an excess of chromosome fissions in the human lineage or an excess of chromosome Fusions in the zebrafish lineage? Comparative analysis suggests that an excess of chromosome fissions in the tetrapod lineage may account for chromosome numbers and provides histories for several human chromosomes.