Comparative genetic study confirms exceptionally low genetic variation in the ancient and endangered relictual conifer, Wollemia nobilis (Araucariaceae)
Comparative genetic study confirms exceptionally low genetic variation in the ancient and endangered relictual conifer, Wollemia nobilis (Araucariaceae)
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比较遗传学研究证实，古老且濒临灭绝的遗迹针叶树瓦伦西亚（南洋杉科）的遗传变异极低
作者：
R. Peakall;Daniel P. Ebert;L. Scott;P. F. Meagher;C. Offord
Wollemi松树，Wollemia nobilis（南洋杉科），于1994年被发现，是该属唯一现存的成员，以前只从化石记录中得知。在澳大利亚东南部一个人迹罕至的峡谷中，已知的树木不到100棵，是世界上最濒危的树种之一。利用等位酶、扩增片段长度多态性（AFLP）和简单重复序列（SSR）位点对西葫芦进行了比较群体遗传学研究。nobilis、南洋杉Araucaria cunninghamii和Agathis robusta为两姐妹属的代表。在13个等位酶位点、800多个AFLP位点和20个SSR位点上均未检测到多态性。贵族在Ag。在12个等位酶位点中，只有1个位点变异，800个AFLP位点中有5个位点变异，15个SSR位点中没有一个变异。对于. 800多个AFLP位点中有10个和20个SSR位点中有5个变异。因此，低遗传多样性的特点是所有三个物种。虽然不排除遗传变异的存在，我们的结论是，遗传多样性是非常低的Wollemi松。据我们所知，这是植物中已知的最极端的情况。我们得出结论，小群体效应，克隆性和低于平均水平的遗传变异的组合可能是低多样性的促成因素。沃勒米松的遗传多样性极低，加上其已知的对外来真菌病原体的敏感性，加强了目前严格控制进入松树和松树位置保密的管理政策。
The Wollemi pine, Wollemia nobilis (Araucariaceae), was discovered in 1994 as the only extant member of the genus, previously known only from the fossil record. With fewer than 100 trees known from an inaccessible canyon in southeastern Australia, it is one of the most endangered tree species in the world. We conducted a comparative population genetic survey at allozyme, amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) loci in W. nobilis, Araucaria cunninghamii and Agathis robusta — representatives of the two sister genera. No polymorphism was detected at 13 allozyme loci, more than 800 AFLP loci or the 20 SSR loci screened in W. nobilis. In Ag. robusta only one of 12 allozyme loci, five of 800 AFLP loci and none of the 15 SSR loci were variable. For A. cunninghamii, 10 of > 800 AFLP loci and five of 20 SSR loci were variable. Thus low genetic diversity characterizes all three species. While not ruling out the existence of genetic variation, we conclude that genetic diversity is exceptionally low in the Wollemi pine. To our knowledge this is the most extreme case known in plants. We conclude that the combination of small population effects, clonality and below‐average genetic variation in the family are probable contributing factors to the low diversity. The exceptionally low genetic diversity of the Wollemi pine, combined with its known susceptibility to exotic fungal pathogens, reinforces current management policies of strict control of access to the pines and secrecy of the pine locations.