伯豪生物转化医学服务平台
威斯腾促销
年终盘点

PNAS:日本成功解读腔棘鱼全部染色体组

2012/01/04 来源:新华网
分享: 
导读
日本成功解读了有“活化石”之称的腔棘鱼的全部染色体组,由此发现腔棘鱼具有与哺乳类和爬虫类等陆地动物相同类型的基因,属于鱼类进化到陆地动物的中间类型。这一发现有助于弄清动物由海洋向陆地进化的过程。

近日,国际著名杂志PNAS刊登了日本研究人员的最新研究成果“Genetically distinct coelacanth population off the northern Tanzanian coast”,研究人员们成功解读了有“活化石”之称的腔棘鱼的全部染色体组,由此发现腔棘鱼具有与哺乳类和爬虫类等陆地动物相同类型的基因,属于鱼类进化到陆地动物的中间类型。这一发现有助于弄清动物由海洋向陆地进化的过程。

腔棘鱼是一种活动灵活、鳍呈肢状的肉食鱼类,约3.6亿年前就已在地球上出现,被认为与陆地四足动物远祖有亲缘关系,一直受到全世界研究人员的关注。

东京工业大学等机构研究人员组成的联合研究小组报告说,他们此次研究的是2007年在坦桑尼亚近海捕捞的一条幼鱼。研究人员解读了腔棘鱼约27亿个碱基对,是迄今调查的鱼类染色体组中数目最多的。

研究小组发现,腔棘鱼同时拥有鱼类类型和四足动物类型的基因和重复序列,由此表明腔棘鱼是鱼类和四足动物之间的过渡动物。根据基因配对的比较,研究人员推测,腔棘鱼与陆地动物“同根同源”,在后来的进化过程中才“分道扬镳”。

今后,研究小组准备分析腔棘鱼与四足动物共有的各种基因的功能,寻找鱼类进化为陆地动物的关键,并研究濒危腔棘鱼的遗传多样性。


参考文献

Genetically distinct coelacanth population off the northern Tanzanian coast

Masato Nikaido, Takeshi Sasaki, J. J. Emerson, Mitsuto Aibara, Semvua I. Mzighani, Yohana L. Budeba, Benjamin P. Ngatunga, Masamitsu Iwata, Yoshitaka Abe, Wen-Hsiung Li, and Norihiro Okada

Since the sensational discovery of a living coelacanth off the east coast of South Africa, the geographic distribution of viable coelacanth populations has been a subject of debate. In the past, the coelacanths off the African mainland were thought to be strays from the Comoros because most coelacanths captured were caught in the waters surrounding the Comoros archipelagos. However, in recent years, a large number of coelacanths were captured off the coast of Tanzania, including nine living specimens observed in a remotely operated vehicles survey. Thus, it is possible that there is a reproducing population inhabiting waters off the Tanzania coast. We have sequenced the complete mitochondrial genomes of 21 Tanzanian and 2 Comoran coelacanths and analyzed these sequences together with two additional full mitochondrial genomes and 47 d-loop sequences from the literature. We found that the coelacanth population off the northern Tanzanian coast is genetically differentiated from those of the southern Tanzania coast and the Comoros, whereas no significant genetic differentiation occurs between the latter two localities. The differentiation between the northern and southern Tanzanian coast populations is consistent with the hypothesis that the existence of northward-flowing ocean current along the Tanzanian coast may reduce or prevent gene flow from the northern to the southern population. Finally, we estimated that the population localized to the southern Tanzanian coast and the Comoros diverged from other coelacanths at least 200,000 y ago. These results indicate that the coelacanths off the northern Tanzania coast are not strays but a genetically distinct group. Our study provides important information for the conservation of this threatened “living fossil.”

文献链接:http://www.pnas.org/content/108/44/18009

本网站所有注明“来源:生物探索”的文字、图片和音视频资料,版权均属于生物探索所有,其他平台转载需得到授权。本网所有转载文章系出于传递更多信息之目的,且明确注明来源和作者,不希望被转载的媒体或个人可与我们联系(editor@biodiscover.com),我们将立即进行删除处理。所有文章仅代表作者观点,不代表本站立场。