本周《自然—通讯》期刊发表了白鳍豚（又名白暨豚）的基因组序列 。这项研究有助于了解白鳍豚的生活习性与其被灭绝原因。
白鳍豚是世界上已知五种淡水豚（拉河豚、亚河豚、恒河豚、印河豚、白鳍豚）中存活头数最少的一种，已被公认为“功能性灭绝”。它也是鲸类动物中因人类活动而被灭绝的第一种物种。南京师范大学杨光教授与其科研团队为一头雄性白鳍豚进行了基因组测序，也同时为三头白鳍豚进行了基因组重测序，以便了解鲸类动物的进化适应和导致其数量下降的遗传原因。
通过比较分析，作者发现了一篮子帮助哺乳动物适应水中生活的基因，包括和嗅觉、味觉、视觉、听觉和大脑扩张有关的基因。尽管有证据表明一万年前白鳍豚曾遭遇过‘人口瓶颈’（人口或数量因突然的灾难或不能生育造成而减少50%以上），但是研究结果显示，白鳍豚最终被灭绝的原因不是由‘人口瓶颈’造成，而是由人类在长江的活动而造成。这项研究为研究水生哺乳动物进化和保护提供了宝贵的数据。(生物谷Bioon.com)
生物谷推荐的英文摘要
Nature Communications doi:10.1038/ncomms3708
Baiji genomes reveal low genetic variability and new insights into secondary aquatic adaptations
Xuming Zhou,Fengming Sun,Shixia Xu, Guangyi Fan, Kangli Zhu,Xin Liu,Yuan Chen,Chengcheng Shi,Yunxia Yang, Zhiyong Huang,Jing Chen,Haolong Hou,Xuejiang Guo,Wenbin Chen,Yuefeng Chen, Xiaohong Wang,Tian Lv,Dan Yang, Jiajian Zhou,Bangqing Huang
The baiji, or Yangtze River dolphin (Lipotes vexillifer), is a flagship species for the conservation of aquatic animals and ecosystems in the Yangtze River of China; however, this species has now been recognized as functionally extinct. Here we report a high-quality draft genome and three re-sequenced genomes of L. vexillifer using Illumina short-read sequencing technology. Comparative genomic analyses reveal that cetaceans have a slow molecular clock and molecular adaptations to their aquatic lifestyle. We also find a significantly lower number of heterozygous single nucleotide polymorphisms in the baiji compared to all other mammalian genomes reported thus far. A reconstruction of the demographic history of the baiji indicates that a bottleneck occurred near the end of the last deglaciation, a time coinciding with a rapid decrease in temperature and the rise of eustatic sea level.
