Genetic evaluation of a demographic bottleneck in the Greater Prairie Chicken
Genetic evaluation of a demographic bottleneck in the Greater Prairie Chicken
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DOI：
10.1046/j.1523-1739.1998.97164.x
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发表时间：
1998-08-01
影响因子：
6.3
通讯作者：
Paige, KN
中科院分区：
文献类型：
--
作者：
Bouzat, JL;Cheng, HH;Paige, KN
尽管种群大小、适合度和遗传变异之间的理论关系已经确立，但只有少数研究提供了直接证据，将遗传变异和适合度的下降与自然系统的人口瓶颈联系起来。我们报道了具有不同人口统计学历史的四个大草原鸡（Tympanuchus cupido）群体的遗传比较。具体来说，我们比较了伊利诺斯州的人口，这些人口遭受了极端的人口收缩和相关的人口适应性下降（以孵化率衡量），而堪萨斯州、内布拉斯加州和明尼苏达州的人口没有已知的瓶颈历史或相关的适应性下降。利用聚合酶链反应，我们扩增了6个微卫星位点，从中估计了研究群体的杂合度、等位基因多样性和地理分化（F-ST和R-ST）水平。分析结果表明，伊利诺斯州山鸡的平均等位基因杂合度最低，等位基因多样性约为三分之二，与其他种群的等位基因共享率为95-100%。这一发现表明，伊利诺伊山鸡最初具有更高水平的遗传多样性，但后来由于极端的人口萎缩而失去了遗传多样性。据我们所知，这是由于已知的野生鸟类种群瓶颈导致的遗传多样性丧失与种群适应性下降有关的第一个例子。
Although the theoretical relationship between population size, fitness, and genetic variation is well established, only a few studies have provided direct evidence that ties a decline in both genetic variation and fitness to a demographic bottleneck for a natural system. We report on a genetic comparison of four populations of the Greater Prairie Chicken (Tympanuchus cupido) with different demographic histories. Specifically, we compared a population from Illinois that has suffered an extreme demographic contraction and an associated decline in population fitness (measured in terms of hatchability rates) with populations from Kansas, Nebraska, and Minnesota with no known history of bottlenecks or associated declines in fitness. Using the polymerase chain reaction, we amplified six microsatellite loci from which levels of heterozygosity, allelic diversity, and geographic differentiation (F-ST and R-ST) of the studied populations were estimated. Results of this analysis showed that the Illinois Prairie Chicken had the lowest estimate of mean heterozygosity per locus and approximately two-thirds the allelic diversity, sharing 95-100% of all their alleles with each of the other populations. This finding suggests that the Illinois Prairie Chicken originally had higher levels of genetic diversity that were subsequently lost through an extreme demographic contraction. To our knowledge this is the first example of loss of genetic diversity being associated with a decrease in population fitness as a result of a known demographic bottleneck in a wild bird species.