Population Structure and Dynamics of the Lemon Shark, Negaprion Brevirostris, on a Local and Global Scale: Microsatellite and Mitochondrial DNA Analysis

本地和全球范围内柠檬鲨 (Negaprion Brevirostris) 的种群结构和动态：微卫星和线粒体 DNA 分析

• 批准号: 9712137
• 负责人: Mary Ashley
• 金额: $ 18万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9712137&HistoricalAwards=false
• 关键词: Population; Structure; Dynamics; Lemon; Shark

Comprehensive field and laboratory investigations will be undertaken to determine the local mating system and geographic population structure of the lemon shark, Negaprion brevirostris, a large coastal shark and a tropical apex predator. The research objectives are to: 1) genetically characterize, for the first time, the mating system of a cartilaginous fish; 2) clarify the use of a tropical nursery ground by juvenile sharks and females in paturition; and 3) examine population structure at both a local and extensive geographic scale. The study site at Bimini is unique in that nearly the entire juvenile population in the lagoon can and will be sampled, and genetic analysis of these samples will in large part provide the data for the first two objectives. Specifically, the field component includes a five-year sampling program of which three years have been completed. The data from juveniles will be supplemented by genotyping adults sampled in and around Bimini. The genetic and field data together will provide estimates of the total population size of pups, their growth, survival and movements, the number of females using Bimini as a nursery ground, and the relative reproductive success of males and females within and across years. Finally, the data can document whether individual females are returning to the Bimini nursery areas to give birth and if so, the interbirth intervals for females and the number of males siring their young. The third objective of the study will allow placement of the detailed local genetic structure documented at Bimini within the framework of the species genetic structure as a whole. Population structure at larger geographic scales will be accomplished through sampling 20-30 lemon sharks at four other locations that represent multiple spatial scales and potential barriers to dispersal. These sites include 1) a second Bahamian site (Grand Bahama Island) approximately 100 km across the NW providence channel from Bimini; 2) a second known lemon shark nursery west of the Florida Keys (Marquesas) separated from Bimini by 350 km and the Florida current; 3) a distant Atlantic site off the east coast of Brazil approximately 5000 km from Bimini; and 4) samples from the Pacific coast of Mexico completely isolated from the Atlantic sites by the Isthmus of Panama. Two methods of genetic analysis, microsatellites and mitochodrial DNA (mtDNA), will be employed in this study. Microsatellites exhibit the levels of variability necessary for inferring parent/offspring and sibship relationships at Bimini, especially when supplemented by additional genetic information provided by the maternally inherited mtDNA. The use of unlinked genetic markers having different transmission genetics (mtDNA is maternally inherited and microsatellite loci exhibit Mendelian inheritance) will provide separate but complementary estimates of genetic variation within and among populations, provide estimates of population differentiation and migration rates between the five sites in our study, and distinguish putative differences in patterns of male and female mediated gene flow.

将进行全面的现场和实验室调查，以确定柠檬鲨的当地交配系统和地理种群结构，Negaprion Brevirostris，大型沿海鲨鱼和热带顶点捕食者。 研究目标是：1）首次在基因上表征了软骨鱼的交配系统； 2）阐明少年鲨鱼和雌性在paturition中使用热带托儿所； 3）在局部和广泛的地理量表上检查人口结构。 比米尼（Bimini）的研究地点是独一无二的，因为泻湖中的几乎整个少年人口都可以并且将被采样，并且对这些样本的遗传分析将在很大程度上为前两个目标提供数据。具体而言，现场组件包括一个五年的抽样计划，其中三年已完成。 来自少年的数据将通过在比米尼及其周围及其周围进行的基因分型来补充。 遗传数据和田间数据将共同估计幼崽的总人口大小，其生长，生存和运动，使用Bimini作为托儿所的女性数量以及多年来男性和女性的相对生殖成功。 最后，数据可以记录单个女性是否正在返回比米尼托儿所（Bimini Nursery）区域以分娩，如果是这样，则是女性的分娩间隔以及年轻的男性人数。 该研究的第三个目标将允许将在Bimini的详细局部遗传结构放置在整个物种遗传结构的框架内。较大地理量表的种群结构将通过在其他四个代表多个空间尺度和潜在分散障碍的位置进行抽样20-30个柠檬鲨来实现。 这些地点包括1）第二个巴哈马遗址（大巴哈马岛），横跨比米尼（Bimini）的西北普罗维登斯（NW Providence）频道约100公里； 2）佛罗里达钥匙以西的第二个已知的柠檬鲨苗圃（Marquesas）与比米尼（Bimini）相距350公里，佛罗里达州的电流分开； 3）距离比米尼（Bimini）约5000公里的巴西东海岸附近的一个遥远的大西洋地点； 4）来自墨西哥太平洋海岸的样品完全由巴拿马地峡从大西洋地点隔离。 这项研究将采用两种遗传分析的方法，微卫星和线粒体DNA（mtDNA）。微卫星表现出在比米尼（Bimini）推断父母/后代和sibship关系所需的可变性水平，尤其是在接受母体遗传的mtDNA提供的其他遗传信息补充时。 使用具有不同传播遗传学的非链接遗传标记（mtDNA是母遗传的，Microsatellite基因座表现出Mendelian遗传性）将提供单独的但互补的估计，对种群内部和人群中遗传变异的估计值提供了人口差异和迁移率在我们研究中的五个地点的估计，并在我们的研究中差异化了男性和女性的模式差异。