Farmed Atlantic salmon are one of the most economically significant global aquaculture products. Early sexual maturation of farmed males represents a significant challenge to this industry and has been linked with the vgll3 genotype. However, tools to aid research of this topic, such as all-male and clonal fish, are still lacking. The present 6-year study examined if all-male production is possible in Atlantic salmon, a species with heteromorphic sex chromosomes (males being XY, females XX), and if all-male fish can be applied to further explore the vgll3 contribution on the likelihood of early maturation. Estrogen treatment of mixed sex yolk sac larvae gave rise to one sexually mature hermaphrodite with a male genotype (XY) that was used to produce both self-fertilized offspring and androgenetic double haploid (dh) offspring following egg activation with UV treated sperm and pressure shock to block the first mitotic division. There were YY supermales among both offspring types, which were crossed with dh females. Between 1 and 8% of the putative all-male offspring from the eight crosses with self-fertilized supermales were found to have ovaries, and 95% of these phenotypic females were also genetically female. None of the offspring from the one dh supermale cross had ovaries. When assessing the general contribution of the vgll3 locus on the likelihood of early post-smolt sexual maturation (jacking) in the all-male populations we found individuals that were homozygous for the early maturing genotype (97%) were more likely to enter puberty than individuals that were homozygous for the late maturing genotype (26%). However, the likelihood of jacking within individuals with an early/late heterozygous genotype was higher when the early allele came from the dam (94%) compared to the sire (45%). The present results show that supermale Atlantic salmon are viable and fertile and can be used as a research tool to study important aspects of sexual maturation, such as to further explore the sex dependent parental genetic contribution to age at puberty in Atlantic salmon. In addition, we report the production of viable double haploid supermale fish.

中文翻译：

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开发超雄性和全雄性大西洋鲑鱼以研究 vgll3 等位基因 - 青春期联系


养殖大西洋鲑鱼是全球最具经济意义的水产养殖产品之一。养殖雄性的过早性成熟对该行业构成了重大挑战，并且与 vgll3 基因型有关。然而，仍然缺乏辅助该主题研究的工具，例如全雄性鱼和克隆鱼。目前为期 6 年的研究检验了大西洋鲑鱼（一种具有异形性染色体（雄性为 XY，雌性为 XX）的物种）是否可以进行全雄性生产，以及是否可以应用全雄性鱼来进一步探索 vgll3 对早熟的可能性。对混合性别卵黄囊幼虫进行雌激素处理，产生一种具有雄性基因型 (XY) 的性成熟雌雄同体，在用紫外线处理的精子和压力休克激活卵子后，用于产生自体受精后代和雄激素双单倍体 (dh) 后代阻止第一次有丝分裂。两种后代类型中都有YY超雄性，与dh雌性杂交。八个与自体受精的超级雄性杂交的假定全雄性后代中，有 1% 到 8% 被发现有卵巢，并且这些表型雌性中 95% 在基因上也是雌性。一个 dh 超级雄性杂交的后代都没有卵巢。当评估 vgll3 基因座对所有雄性群体中幼崽后早​​期性成熟（劫持）可能性的一般贡献时，我们发现早熟基因型纯合的个体（97%）比个体更有可能进入青春期。晚熟基因型纯合的个体（26%）。 然而，与父亲 (45%) 相比，当早期等位基因来自母亲 (94%) 时，具有早期/晚期杂合基因型的个体发生顶撞的可能性更高。目前的结果表明，超级雄性大西洋鲑鱼具有存活能力和繁殖力，可用作研究性成熟重要方面的研究工具，例如进一步探索性别依赖性亲本遗传对大西洋鲑鱼青春期年龄的贡献。此外，我们报告了可存活的双单倍体超级雄性鱼的生产。