Sexual maturation timing is a life-history trait central to the balance between mortality and reproduction. Maturation may be triggered when an underlying compound trait, called liability, exceeds a threshold. In many different species and especially fishes, this liability is approximated by growth and body condition. However, environmental vs. genetic contributions either directly or via growth and body condition to maturation timing remain unclear. Uncertainty exists also because the maturation process can reverse this causality and itself affect growth and body condition. In addition, disentangling the contributions of polygenic and major loci can be important. In many fishes, males mature before females, enabling the study of associations between male maturation and maturation-unbiased female liability traits. Using 40 Atlantic salmon families, longitudinal common-garden experimentation, and quantitative genetic analyses, we disentangled environmental from polygenic and major locus (vgll3) effects on male maturation, and sex-specific growth and condition. We detected polygenic heritabilities for maturation, growth, and body condition, and vgll3 effects on maturation and body condition but not on growth. Longitudinal patterns for sex-specific phenotypic liability, and for genetic variances and correlations between sexes suggested that early growth and condition indeed positively affected maturation initiation. However, towards spawning time, causality appeared reversed for males whereby maturation affected growth negatively and condition positively via both the environmental and genetic effects. Altogether, the results indicate that growth and condition are useful traits to study liability for maturation initiation, but only until maturation alters their expression, and that vgll3 contributes to maturation initiation via condition.

中文翻译：

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大西洋鲑鱼性成熟时间的多基因和主要位点贡献

性成熟时间是平衡死亡率和繁殖之间的核心生命史特征。当称为责任的潜在复合特征超过阈值时，可能会触发成熟。在许多不同的物种，尤其是鱼类中，这种负担与生长和身体状况有关。然而，环境与遗传直接或通过生长和身体状况对成熟时间的贡献仍不清楚。不确定性的存在也​​是因为成熟过程可以逆转这种因果关系，并且本身会影响生长和身体状况。此外，解开多基因位点和主要位点的贡献可能很重要。在许多鱼类中，雄性先于雌性成熟，从而能够研究雄性成熟与成熟无偏见的雌性责任特征之间的关联。使用 40 个大西洋鲑鱼科，vgll3 ) 对雄性成熟和性别特异性生长和状况的影响。我们检测到成熟、生长和身体状况的多基因遗传力，以及vgll3对成熟和身体状况的影响，但对生长没有影响。性别特异性表型倾向的纵向模式以及性别之间的遗传差异和相关性表明，早期生长和状况确实对成熟的开始产生了积极的影响。然而，在产卵期，雄性的因果关系似乎相反，成熟通过环境和遗传效应对生长产生负面影响，对条件产生积极影响。总而言之，结果表明，生长和条件是研究成熟开始责任的有用特征，但仅在成熟改变它们的表达之前，并且vgll3通过条件促进成熟启动。