Genetic basis for variation in salinity tolerance between stickleback ecotypes
Genetic basis for variation in salinity tolerance between stickleback ecotypes
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DOI：
10.1111/mec.13875
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发表时间：
2017-01-01
影响因子：
4.9
通讯作者：
Kitano, Jun
中科院分区：
文献类型：
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作者：
Kusakabe, Makoto;Ishikawa, Asano;Kitano, Jun
对不同盐度的适应可以驱动和维持水生生物种群之间的分化。溯河产卵和溪流生态类型的三刺鱼（Gasterosteus aculeatus）是一个很好的模式，探讨遗传机制的调节分歧。使用一对parapatric溯河产卵和流刺鱼生态型，我们采用了一个综合的基因组方法，以确定候选基因的重要适应不同的盐度环境。海水挑战实验下的血浆钠浓度的数量性状基因座（QTL）定位确定了显着的QTL 16号染色体上。为了确定该QTL内的候选基因，我们首先对鳃组织进行了RNA-seq和微阵列分析，以发现与血浆Na+水平相关的基因表达的生态差异。这导致了10个候选基因的鉴定。对其他日本棘鱼种群鳃组织的定量PCR分析显示，大多数候选基因在表达水平上表现出平行的分歧。其次，我们进行了全基因组测序，发现了五个预测具有重要功能的氨基酸取代的基因。最后，我们进行了基因组扫描分析，发现这些候选基因中有8个位于高分化的基因组岛上，这表明它们可能受到趋异选择的影响。候选基因包括参与ATP合成和激素信号传导的基因，其表达或氨基酸变化可能是耐盐性变化的基础。对这些基因的进一步功能分子分析将揭示趋异适应背后的致病性遗传和基因组变化。
Adaptation to different salinities can drive and maintain divergence between populations of aquatic organisms. Anadromous and stream ecotypes of threespine stickleback (Gasterosteus aculeatus) are an excellent model to explore the genetic mechanisms underlying osmoregulation divergence. Using a parapatric pair of anadromous and stream stickleback ecotypes, we employed an integrated genomic approach to identify candidate genes important for adaptation to different salinity environments. Quantitative trait loci (QTL) mapping of plasma sodium concentrations under a seawater challenge experiment identified a significant QTL on chromosome 16. To identify candidate genes within this QTL, we first conducted RNA-seq and microarray analysis on gill tissue to find ecotypic differences in gene expression that were associated with plasma Na+ levels. This resulted in the identification of ten candidate genes. Quantitative PCR analysis on gill tissue of additional Japanese stickleback populations revealed that the majority of the candidate genes showed parallel divergence in expression levels. Second, we conducted whole-genome sequencing and found five genes that are predicted to have functionally important amino acid substitutions. Finally, we conducted genome scan analysis and found that eight of these candidate genes were located in genomic islands of high differentiation, suggesting that they may be under divergent selection. The candidate genes included those involved in ATP synthesis and hormonal signalling, whose expression or amino acid changes may underlie the variation in salinity tolerance. Further functional molecular analysis of these genes will reveal the causative genetic and genomic changes underlying divergent adaptation.