Fisheries College, Ocean University of China, Qingdao 266003, China.
Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
Int J Mol Sci. 2023 Dec 8;24(24):17262. doi: 10.3390/ijms242417262.
High mortalities and highly variable results during the subsequent development of post-thaw larvae have been widely considered as key issues restricting the application of cryopreservation techniques to support genetic improvement programs and hatchery production in farmed marine bivalve species. To date, few studies have been undertaken to investigate the effects of cryodamage at the molecular level in bivalves. This study is the first to evaluate the effect of larval cryopreservation on the epigenetics of the resultant progenies of the Pacific oyster . The results show that the level of DNA methylation was significantly ( < 0.05) higher and lower than that of the control when the trochophore larvae were revived and when they developed to D-stage larvae (day 1 post-fertilization), respectively, but the level returned to the control level from day 8 post-fertilization onwards. The expression of the epigenetic regulator genes , 2, , and changed significantly ( < 0.05) when the trochophore larvae were thawed, and then they reverted to the control levels at the D- and later larval developmental stages. However, the expression of other epigenetic regulator genes, namely, , , and , did not change at any post-thaw larval developmental stage. For the newly thawed trochophore larvae, the amount of methylated H3K4Me1 and H3K27Me1 significantly changed, and the expression of all orthologs, except that of significantly ( < 0.05) decreased. These epigenetic results agree with the data collected on larval performances (e.g., survival rate), suggesting that the effect period of the published cryopreservation technique on post-thaw larvae is short in .
在随后的解冻幼虫发育过程中，高死亡率和高度可变的结果一直被广泛认为是限制冷冻保存技术应用于支持遗传改良计划和养殖海洋双壳类孵化生产的关键问题。迄今为止，很少有研究探讨冷冻损伤对贝类分子水平的影响。本研究首次评估了幼虫冷冻保存对太平洋牡蛎幼虫遗传后代表观遗传学的影响。结果表明，当担轮幼虫复苏时和发育到 D 期幼虫（受精后第 1 天）时，DNA 甲基化水平分别显著高于（<0.05）和低于（<0.05）对照组，但从受精后第 8 天开始，水平恢复到对照组水平。当担轮幼虫解冻时，表观遗传调控基因、、和的表达显著（<0.05）改变，然后在 D 期及以后的幼虫发育阶段恢复到对照组水平。然而，其他表观遗传调控基因，即、、和的表达在任何解冻后幼虫发育阶段都没有改变。对于新解冻的担轮幼虫，甲基化 H3K4Me1 和 H3K27Me1 的量显著改变，除了显著（<0.05）降低外，所有同源基因的表达都降低。这些表观遗传学结果与幼虫性能（如存活率）数据一致，表明在中，公布的冷冻保存技术对解冻后幼虫的影响期较短。
