生物谷报道:综合大熊猫化石及现生种体型大小变化、食物特化、种群数量急剧下降、栖息地破碎化、圈养种群繁殖衰退和竹子开花等多方面研究,传统的观点认为大熊猫的濒危是进化历程的必然。记者今天从中国科学院动物研究所了解到,由该所研究员魏辅文领导的研究小组最新完成的一项研究成果表明,大熊猫并未走到进化历史的尽头,仍然具有进化潜力。该成果发表于近期出版的进化生物学领域权威期刊《分子生物学与进化》上。
魏辅文小组在中科院海外创新团队项目和国家杰出青年基金的资助下,与四川省林业厅、英国卡迪夫大学、西华师范大学等单位的专家合作,采用群体遗传学的研究方法,对现存大熊猫种群遗传多样性与变异、种群遗传结构与基因流、种群动态历史等问题进行深入讨论。发现该物种现生种群仍保持较高的遗传多样性和长期续存的进化潜力,大熊猫在末次冰期消融后还经历了强烈的种群扩张,而现生种群的衰退仅始于几千年前。这一结果提示大熊猫种群的濒危和中国历史上人口不断增长所带来的压力密切相关。上述发现修正了长久以来公众对大熊猫前途命运的认识,表明大熊猫并非处于进化历史尽头的孑遗物种,而仍是具有进化潜力的美丽生灵。大熊猫的濒危由自身以外的因素造成,而人类应为其种群濒危负有不可推卸的责任。
大熊猫憨态可掬的外表、以竹为生的独特食性、不为人所知的生活习性等,使它几乎成为世界范围内最受关注的物种、世界自然保护的象征。近年来,我国野生大熊猫的调查结果显示,其栖息地质量逐步改善,种群数量已有回升的良好势头。这一方面表明我国政府所采取的一系列保护措施——如实施大熊猫栖息地保护工程、天然林保护工程和退耕还林工程,建立大熊猫自然保护区网络等——正日益凸现出其生态效益;另一方面,也表明现生大熊猫种群仍保持勃勃生机,为其并未走到进化历史尽头提供了佐证。(科学时报)
原始出处:
MBE Advance Access originally published online on May 19, 2007
Molecular Biology and Evolution 2007 24(8):1801-1810; doi:10.1093/molbev/msm099
Genetic viability and population history of the giant panda, putting an end to the evolutionary dead-end
Baowei Zhang*, Ming Li*, Zejun Zhang*,, Benoît Goossens, Lifeng Zhu*, Shanning Zhang*, Jinchu Hu, Michael W. Bruford and Fuwen Wei*,
* Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, the Chinese Academy of Sciences, Haidian, Beijing, People's Republic of China
Biodiversity and Ecological Processes Group, School of Biosciences, Cardiff University, Cardiff, United Kingdom
Institute of Rare Animals and Plants, China West Normal Univeristy, Nanchong, Sichuan, People's Republic of China
Corresponding author: Fuwen Wei, Tel: +86-010-64807152, Fax: +86-010-64807099, E-mail: weifw@ioz.ac.cn
Received for publication November 26, 2006. Revision received April 10, 2007. Accepted for publication May 15, 2007.
The giant panda (Ailuropoda melanoleuca) is currently threatened by habitat loss, fragmentation and human persecution. Its dietary specialization, habitat isolation and reproductive constraints have led to a perception that this is a species at an ‘evolutionary dead-end’, destined for deterministic extinction in the modern world. Here, we examine this perception by a comprehensive investigation of its genetic diversity, population structure and demographic history across its geographic range. We present analysis of 655 base pairs of mitochondrial (mt) control region (CR) DNA and ten microsatellite loci for samples from its five extant mountain populations (Qinling, Minshan, Qionglai, Liangshan and Lesser Xiangling). Surprisingly, extant populations display average to high levels of CR and microsatellite diversity compared with other bear species. Genetic differentiation among populations was significant in most cases but was markedly higher between Qinling and the other mountain ranges, suggesting, minimally, that the Qinling population should comprise a separate management unit for conservation purposes. Recent demographic inference using microsatellite markers demonstrated a clear genetic signature for population decline starting several thousands years ago or even futher back in the past, and being accelerated and enhanced by the expansion of human populations. Importantly, these data suggest that the panda is not a species at an evolutionary ‘dead-end’, but in common with other large carnivores, has suffered demographically at the hands of human pressure. Conservation strategies should therefore focus on the restoration and protection of wild habitat and the maintenance of the currently substantial regional genetic diversity, through active management of disconnected populations.
Key Words: giant panda • genetic diversity • population structure • population demography • evolutionary dead-end