Heritability of acute low salinity survival in the Eastern oyster (Crassostrea virginica)
Heritability of acute low salinity survival in the Eastern oyster (Crassostrea virginica)
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DOI：
10.1016/j.aquaculture.2020.735649
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发表时间：
2020-12
期刊：
影响因子：
4.5
通讯作者：
Alexandra J. McCarty;K. McFarland;J. Small;S. Allen;L. Plough
中科院分区：
文献类型：
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作者：
Alexandra J. McCarty;K. McFarland;J. Small;S. Allen;L. Plough
在美国东海岸，东方牡蛎(Crassostrea Virgiica)水产养殖业在上个世纪得到了大幅增长。随着水产养殖扩展到以前未开发的地区，需要针对特定环境条件培育牡蛎品系。在切萨皮克湾的马里兰部分和其他沿海地区，盐度往往低于典型水产养殖生产力的最佳水平，这些地区经常在暴雨事件之后经历严重的低盐度时期。虽然这些区域可能会阻碍牡蛎的生长，但它们提供了一个躲避常见牡蛎疾病的避难所。专注于在急性低盐度条件下生存的选择性育种可以扩大适合水产养殖的区域，但这一特征背后的遗传框架目前尚不清楚。在这项研究中，我们通过对50个同父异母的兄弟姐妹家庭进行两个月的低盐度暴露实验，估计了在急性低盐度(<；3)下存活的遗传力。在第二次暴露实验的前8天，分析血淋巴渗透压，以跟踪渗透构象行为，并调查潜在的生理差异，在盐度生存的家庭之间的变化。在两个低盐度暴露实验中，家庭之间的死亡率存在显著差异，两个实验的大部分死亡发生在暴露后8至14天之间。在第二次实验中观察到总体死亡率较高(实验2为53%，实验1为23%)，该实验在动物繁殖活跃的夏季进行。使用贝叶斯(MCMCglmm，实验1，H2=0.34，实验2，0.59)和基于可能性(ASReml-R，两个实验的H2=60.4)方法，狭义的生存遗传力估计是中等到高的，并且ASReml-R的估计似乎低于实验2的MCMCglmm(ASReml-R H2=90.4，MCMCglmm H2=100.59)。最后，在两个采样日，不同家庭的渗透压没有差异，但在盐度保持在我们希望的水平(2.5)后，所有家庭都保持了轻微的高渗透。这项研究首次对急性低盐度生存公司进行了定量遗传分析。维吉尼亚和研究结果表明，这种性状是可遗传的，可以在育种计划中进行选择。
On the US east coast, Eastern oyster (Crassostrea virginica) aquaculture has grown substantially over the last century. As aquaculture expands into previously unexploited areas, there is a need for oyster lines bred for specific environmental conditions. In the Maryland portion of the Chesapeake Bay, and in other coastal areas, salinity tends to be below optimal for typical aquaculture productivity, and these areas frequently experience periods of acute low salinity following heavy rain events. While these areas may hinder oyster growth, they provide a refuge from common oyster diseases. Selective breeding focusing on survival in acute low salinity conditions could expand areas suitable for aquaculture, but the genetic framework underlying this trait is currently unknown. In this study, we estimated the heritability of survival at acute low salinity (< 3) by conducting two month-long low salinity exposure experiments with fifty half-sibling families. Hemolymph osmolality was analyzed during the first eight days of the second exposure experiment to track osmoconformation behavior and investigate potential physiological differences underlying variation in salinity survival among families. There were significant differences in mortality among families for both low salinity exposure experiments, with the majority of mortality occurring between 8 and 14 days of exposure for both experiments. Higher overall mortality was observed during the second experiment (53% in experiment 2 versus 23% in experiment 1), which was conducted during the summer when animals were reproductively active. Narrow-sense heritability estimates for survival were moderate to high using both a Bayesian (MCMCglmm, h2= 0.34 for experiment 1 and 0.59 for experiment 2) and a likelihood-based (ASReml-R, h2= 0.4 for both experiments) approach, and estimates from ASReml-R appeared to be lower compared to MCMCglmm for experiment 2 (ASReml-R h2= 0.4, MCMCglmm h2= 0.59). Finally, there were no differences in osmolality among families on either sampling day, but all families remained slightly hyperosmotic after salinity was held static at our desired level (2.5). This study provides the first quantitative genetic analysis of acute low salinity survival inC. virginicaand results suggest that this trait is heritable and could be selectable in a breeding program.