圈养大熊猫个体与放归地小种群景观遗传的兼容性研究

The giant panda (Ailuropoda melanoleuca) is one of the worlds most charismatic endangered species and also a flagship species for the conservation movement worldwide. Now the giant panda is confined to six fragmented mountain habitats at the edge of the Tibetan Plateau, and are restricted to approximately 20 isolated populations in the worldwide. Many small isolated populations have been confronted with population decline and loss of genetic diversity. These isolated populations are in danger of becoming extinct without effective protection. The reintroduction of captive bred animals is a vital tool for the conservation of endangered species in the wild. For captive bred species with known pedigrees, individual animals can be selected to create reintroduced populations with speci?c genetic compositions. Several attempts of reintroduction programs have been performed on giant panda, however, none have yet to be successful. One reason for these failed attempts is that most programs do not take full advantage of the potential afforded by monitoring the population genetic background of captive populations as well as the small isolated populations in the wild. Otherwise, captive breeding and reintroduction programs could potentially be counterproductive if the genetic consequences of the various management options are not fully considered. Because of this, we intend to perform a detailed population genetic and spatial landscape genetic analysis on captive bred giant pandas and the small isolated populations using noninvasive genetic sampling from feces, to address four issues as follows: consummate the pedigree of captive bred giant pandas; compare the genetic diversity and relationship between captive bred giant pandas and the isolated populations; analyze the population genetic structure of the wild fragmented population as well as their population history and spatial genetic structure; screen captive bred individuals which hold high genetic diversity for disease resistance and strong adaptability to the wild habitat.

大熊猫（Ailuropoda melanoleuca）是我国特有的珍稀濒危动物，是国际野生动物保护的旗舰物种，现今仅分布于岷山、邛崃、大相岭、小相岭、凉山、秦岭等六个山系中。其野生种群被分割成20多个孤立小种群，很多小种群数量急剧下降，遗传多样性丧失，濒临灭绝。通过从圈养种群中挑选合适的野外放归个体释放到野生小种群中去是长期保护与复壮小种群的非常重要的技术手段。但是，已经进行的大熊猫野外放归尝试缺乏对圈养种群和野外放归目的地小种群遗传背景的比较研究，从而影响放归成功率。本研究拟通过对圈养大熊猫种群和野外孤立小种群进行非损伤性遗传取样，利用分子遗传学和景观遗传学研究方法，完善圈养大熊猫遗传谱系，探明野外孤立小种群的种群数量和性别比例，比较圈养大熊猫种群与野外孤立小种群的遗传多样性水平和二者之间的亲缘关系及景观遗传格局兼容性，筛选出适于放归的圈养个体和确定景观遗传兼容的放归目的地。

动物放归能改善孤立小种群的种群数量和遗传多样性以及减少近亲繁殖，从而维持该种群在自然界长期进化发展的潜力。圈养大熊猫（Ailuropoda melanoleuca）的野化放归，面临着种群遗传兼容性挑战。.本研究通过对圈养和野外大熊猫种群进行非损伤性遗传取样，利用分子遗传学研究方法，完善圈养大熊猫遗传谱系，探明野外孤立小种群的种群数量，比较圈养大熊猫种群与野外种群的遗传多样性水平和二者之间的遗传格局兼容性，确定潜在放归目的地和筛选景观遗传兼容的圈养个体。.使用12对微卫星标记对494份野外大熊猫样品DNA基因分型，确定这些样品来自于四大山系五大分布区域21县（市）的221个个体；圈养种群则有67个个体得到了可靠的基因型。研究结果表明：.圈养大熊猫种群的平均等位基因数（A）为5，低于岷山山系种群（6.8）、岷山-邛崃过渡带种群（6）和邛崃山系种群（5.6），但是却高于小相岭山系种群（3.8）和凉山山系种群（4.4）；平均表观杂合度（Ho）则在研究种群中居首。结果表明圈养大熊猫种群依然保持着较高的遗传多样性，且具有展开野化放归以达到改善部分孤立小种群遗传多样性的潜力；.小相岭的种群经历了种群瓶颈，且等位基因频率偏低，美姑县、茂县、峨边县和甘洛县种群的遗传多样性指数均明显低于圈养种群，均是圈养大熊猫潜在放归地。.Structure分析表明圈养种群有部分个体与五大分布区域种群形成遗传基因簇，同时在小相岭种群和凉山种群均出现新的基因频率，表明圈养种群如果放归这些地区，能增加该地区大熊猫种群的遗传多样性；.对圈养大熊猫种群中的秦岭后裔和岷山-邛崃-凉山后裔两个祖系遗传背景比较研究发现岷山-邛崃-凉山祖系的个体具有更大的野化放归潜力且具有与潜在放归栖息地孤立小种群更好的遗传兼容性。.大熊猫种群谱系管理与繁殖技术保证了圈养大熊猫种群较高的遗传多样性，本研究建立了相应的野化放归奠基者种群，其中的适龄个体是我们野化放归个体备选目标或亲本。.本研究为筛选潜在放归栖息地和野化放归圈养个体提供了理论依据。