Comparative genetic structure reflects underlying life histories of three sympatric small mammal species in continuous forest of south-eastern Australia
Comparative genetic structure reflects underlying life histories of three sympatric small mammal species in continuous forest of south-eastern Australia
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DOI：
10.1111/j.0030-1299.2007.16087.x
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发表时间：
2007-11-01
期刊：
影响因子：
3.4
通讯作者：
Wertheim, B.
中科院分区：
文献类型：
--
作者：
Kraaijeveld-Smit, F. J. L.;Lindenmayer, D. B.;Wertheim, B.
栖息地破碎化、种群规模和遗传结构之间存在密切联系。然而，要充分了解破碎化对种群生存能力的长期影响，有必要首先了解非破碎化生境中生活史性状和遗传特征之间的关系。这是最好的做法，通过比较模式的遗传多样性在同域物种，因为相关数据可能是最大的信息。我们比较了三种同域小型哺乳动物（其中两种是有袋类动物）的遗传结构和多样性，在一个小的空间尺度（< 4公里），使用微卫星基因型数据，从四个网格采样的个人以线性方式。所有三个物种的预期杂合性都很高（平均H，范围：0.781-0.886），但最小的物种比两个较大的物种具有显着更高的遗传多样性（杂合性和等位基因多样性），可能是由于它具有; 1）有效种群规模大，世代重叠少，和/或2）大等位基因的突变率高。基因型隔离的距离（测量相关性）仅在最小的距离750英寸，任何物种。在两个有袋类物种I F-ST，相关性和百分比的个人分配到网站的捕获显着低于男性比女性，证实了以前的报告，男性偏见的传播。然而，性别偏见的传播没有检测到的第三个物种（本地灌木鼠fuscipes），并存在显着的杂合缺陷表明，这导致近亲繁殖内亲属结构的demes。我们推测，栖息地碎片化将有不同的影响，人口动态，社会组织和交配系统的两个有袋类物种相比，本地鼠啮齿动物，由于其不同的人口结构和不同的近亲繁殖避免机制。
There are strong links between habitat fragmentation, population size and genetic structure. However, to fully understand the long-term effects of fragmentation on population viability, it is necessary to first understand the relationship between life history traits and genetic characteristics in un-fragmented habitats. This is best done through comparing patterns of genetic diversity in sympatric species, since relative data may be maximally informative. We compared genetic structure and diversity among three sympatric small mammals - of which two were marsupial species - over a small spatial scale (< 4 km) using microsatellite genotypic data from individuals sampled from four grids spaced in a linear fashion. Expected heterozygosity was high for all three species (average H, range: 0.781-0.886), but the smallest species had significantly higher genetic diversity (both heterozygosity and allelic diversity) than the two larger species, possibly due to it having; 1) large effective population size and little overlap in generations, and/or 2) high mutation rates in large alleles. Genotypic isolation by distance (measured as relatedness) was detected only at the smallest distance of 750 in, for any species. In the two marsupial species I F-st, relatedness and percentage of individuals assigned to site of capture were significantly lower in males than in females, corroborating previous reports of male-biased dispersal. However, sex-biased dispersal was not detected for the third species (the native bush rat Rattus fuscipes), and presence of significant heterozygous deficits suggested this resulted in inbreeding within kin-structured demes. We speculate that habitat fragmentation will have differing effects on population dynamics, social organisation and mating systems for the two marsupial species compared to the native murid rodent, due to their differing population structure and divergent inbreeding avoidance mechanisms.