Ujvari Beata, Dowton Mark, Madsen Thomas
School of Biological Sciences, University of Wollongong, NSW 2522, Australia.
Mol Ecol. 2008 Aug;17(15):3557-64. doi: 10.1111/j.1365-294x.2008.03849.x.
By using both mitochondrial and nuclear multiloci markers, we explored population genetic structure, gene flow and sex-specific dispersal of frillneck lizards (Chlamydosaurus kingii) sampled at three locations, separated by 10 to 50 km, in a homogenous savannah woodland in tropical Australia. Apart from a recombinant lizard, the mitochondrial analyses revealed two nonoverlapping haplotypes/populations, while the nuclear markers showed that the frillneck lizards represented three separate clusters/populations. Due to the small population size of the mtDNA, fixation may occur via founder effects and/or drift. We therefore suggest that either of these two processes, or a combination of the two, are the most likely causes of the discordant results obtained from the mitochondrial and the nuclear markers. In contrast to the nonoverlapping mitochondrial haplotypes, in 12 out of 74 lizards, mixed nuclear genotypes were observed, hence revealing a limited nuclear gene flow. Although gene flow should ultimately result in a blending of the populations, we propose that the distinct nuclear population structure is maintained by frequent fires resulting in local bottlenecks, and concomitant spatial separation of the frillneck lizard populations. Limited mark-recapture data and the difference in distribution of the mitochondrial and nuclear markers suggest that the mixed nuclear genotypes were caused by juvenile male-biased dispersal.
通过使用线粒体和核多位点标记，我们研究了在澳大利亚热带地区一片同质的稀树草原林地中，于三个相距10至50公里的地点采集的褶边蜥（Chlamydosaurus kingii）的种群遗传结构、基因流和性别特异性扩散情况。除了一只重组蜥蜴外，线粒体分析揭示了两种不重叠的单倍型/种群，而核标记显示褶边蜥代表三个独立的聚类/种群。由于线粒体DNA的种群规模较小，固定可能通过奠基者效应和/或漂变发生。因此，我们认为这两个过程中的任何一个，或两者的组合，是从线粒体和核标记获得不一致结果的最可能原因。与不重叠的线粒体单倍型相反，在74只蜥蜴中的12只中观察到了混合核基因型，从而揭示了有限的核基因流。尽管基因流最终应导致种群的混合，但我们认为独特的核种群结构是由频繁火灾导致的局部瓶颈以及褶边蜥种群随之而来的空间隔离所维持的。有限的标记重捕数据以及线粒体和核标记分布的差异表明，混合核基因型是由幼年雄性偏向的扩散造成的。
