The recruitment sweepstakes has many winners:: Genetic evidence from the sea urchin Strongylocentrotus purpuratus
The recruitment sweepstakes has many winners:: Genetic evidence from the sea urchin Strongylocentrotus purpuratus
复制标题
DOI：
10.1111/j.0014-3820.2002.tb01456.x
复制
发表时间：
2002-07-01
期刊：
影响因子：
3.3
通讯作者：
Burton, RS
中科院分区：
文献类型：
--
作者：
Flowers, JM;Schroeter, SC;Burton, RS
由于在不可预测的近岸环境中自由产卵，繁殖量大、繁殖前死亡率高的海洋物种在繁殖成功方面可能会出现极端差异。如果海洋的不可预测性导致每个幼虫群中只有一小部分成年种群做出贡献，那么繁殖可能被视为一种抽奖，由偶然事件决定每个产卵季节哪个成年种群成功。这种繁殖抽奖的情况可能部分解释了海洋物种的有效种群规模相对于普查种群规模的大幅减少。我们通过检验对抽奖繁殖成功假说的两个预测进行了评估：(1)相对于成年种群，海胆新兵是否含有较少的遗传变异；(2)海胆招募群体是否存在基因分化。线粒体DNA序列收集了283名最近定居的紫色圆梭菌新兵的线粒体DNA序列，这些新兵来自加利福尼亚各地为期七年的四个年度队列。观察到的单倍型数量和单倍型多样性表明，与先前报道的145个紫斑紫荆成虫样本的多样性相比，新兵的遗传变异减少的证据很少。在某些情况下，不同的新兵群体彼此之间有轻微的差别。抽奖招募的计算机模拟表明，我们的抽样策略有足够的统计能力来检测繁殖成功率的大差异。
As a consequence of free spawning in the unpredictable nearshore environment, marine species with large fecundities and high pre-reproductive mortality may be subject to extreme variance in reproductive success. If the unpredictability of the ocean results in only a small subset of the adult population contributing to each larval cohort, then reproduction may be viewed as a sweepstakes, with chance events determining which adults are successful each spawning season. Such a reproductive sweepstakes scenario may partially account for large reductions in effective population sizes relative to census population sizes in marine species. We evaluated two predictions of the sweepstakes reproductive success hypothesis by testing: (1) whether sea urchin recruits contain reduced genetic variation relative to the adult population; and (2) whether cohorts of sea urchin recruits are genetically differentiated. Mitochondrial DNA sequences were collected from 283 recently settled Strongylocentrotus purpuratus recruits from four annual cohorts spanning seven years in locations throughout California. Observed haplotype numbers and haplotype diversities showed little evidence of reduced genetic variation in the recruits relative to the diversity estimated from a previously reported sample of 145 S. purpuratus adults. Different cohorts of recruits were in some cases mildly differentiated from each other. A computer simulation of sweepstakes recruitment indicates that our sampling strategy had sufficient statistical power to detect large variances in reproductive success.