Budd Alyssa M, Robins Julie B, Whybird Olivia, Jerry Dean R
Centre for Sustainable Tropical Fisheries and Aquaculture James Cook University Townsville Qld Australia.
Centre for Tropical Bioinformatics and Molecular Biology James Cook University Townsville Qld Australia.
Ecol Evol. 2022 Mar 18;12(3):e8730. doi: 10.1002/ece3.8730. eCollection 2022 Mar.
Phenotypic plasticity is an important driver of species resilience. Often mediated by epigenetic changes, phenotypic plasticity enables individual genotypes to express variable phenotypes in response to environmental change. Barramundi () are a protandrous (male-first) sequential hermaphrodite that exhibits plasticity in length-at-sex change between geographic regions. This plasticity is likely to be mediated by changes in DNA methylation (DNAm), a well-studied epigenetic modification. To investigate the relationships between length, sex, and DNAm in a sequential hermaphrodite, here, we compare DNAm in four conserved vertebrate sex-determining genes in male and female barramundi of differing lengths from three geographic regions of northern Australia. Barramundi first mature as male and later sex change to female upon the attainment of a larger body size; however, a general pattern of increasing female-specific DNAm markers with increasing length was not observed. Significant differences in DNAm between males and females of similar lengths suggest that female-specific DNAm arises rapidly during sex change, rather than gradually with fish growth. The findings also reveal that region-specific differences in length-at-sex change are accompanied by differences in DNAm and are consistent with variability in remotely sensed sea temperature and salinity. Together, these findings provide the first evidence for epigenetically and environmentally mediated sex change in a protandrous hermaphrodite and offer significant insight into the molecular and ecological processes governing the marked and unique plasticity of sex in fish.
表型可塑性是物种恢复力的一个重要驱动因素。表型可塑性通常由表观遗传变化介导，使个体基因型能够根据环境变化表达可变的表型。尖吻鲈（）是一种雄性先熟的（雄性优先）序列性雌雄同体鱼类，在不同地理区域之间的性转变体长方面表现出可塑性。这种可塑性可能由DNA甲基化（DNAm）的变化介导，DNA甲基化是一种经过充分研究的表观遗传修饰。为了研究序列性雌雄同体鱼类的体长、性别和DNAm之间的关系，在这里，我们比较了来自澳大利亚北部三个地理区域、不同体长的雄性和雌性尖吻鲈中四个保守的脊椎动物性别决定基因的DNAm情况。尖吻鲈最初成熟时为雄性，在达到更大体型后会转变为雌性；然而，并未观察到随着体长增加，雌性特异性DNAm标记普遍增加的模式。相似体长的雄性和雌性之间DNAm的显著差异表明，雌性特异性DNAm是在性别转变过程中迅速出现的，而不是随着鱼类生长逐渐产生的。研究结果还表明，性转变体长的区域特异性差异伴随着DNAm的差异，并且与遥感海温及盐度的变化一致。这些发现共同为雄性先熟雌雄同体鱼类中表观遗传和环境介导的性别转变提供了首个证据，并为控制鱼类显著且独特的性别可塑性的分子和生态过程提供了重要见解。
