Department of Psychology, University of Houston, Houston, TX 77004;
Department of Biology and Biochemistry, University of Houston, Houston, TX 77004.
Proc Natl Acad Sci U S A. 2020 Nov 10;117(45):28167-28174. doi: 10.1073/pnas.2008925117. Epub 2020 Oct 26.
Social hierarchies are ubiquitous in social species and profoundly influence physiology and behavior. Androgens like testosterone have been strongly linked to social status, yet the molecular mechanisms regulating social status are not known. The African cichlid fish is a powerful model species for elucidating the role of androgens in social status given their rich social hierarchy and genetic tractability. Dominant males possess large testes and bright coloration and perform aggressive and reproductive behaviors while nondominant males do not. Social status in is in flux, however, as males alter their status depending on the social environment. Due to a teleost-specific whole-genome duplication, possess two androgen receptor (AR) paralogs, and , providing a unique opportunity to disentangle the role of gene duplication in the evolution of social systems. Here, we used CRISPR/Cas9 gene editing to generate AR mutant and performed a suite of experiments to interrogate the mechanistic basis of social dominance. We find that but not , is required for testes growth and bright coloration, while , but not , is required for the performance of reproductive behavior and aggressive displays. Both receptors are required to reduce flees from females and either AR is sufficient for attacking males. Thus, social status in is inordinately dissociable and under the modular control of two AR paralogs. This type of nonredundancy may be important in facilitating social plasticity in and other species whose social status relies on social experience.
社会等级在社会性物种中普遍存在，深刻影响着生理和行为。雄激素如睾酮与社会地位密切相关，但调节社会地位的分子机制尚不清楚。非洲丽鱼是阐明雄激素在社会地位中的作用的强大模式物种，因为它们具有丰富的社会等级制度和遗传可操作性。优势雄性具有大的睾丸和鲜艳的颜色，并表现出攻击性和生殖行为，而非优势雄性则没有。然而，由于社会环境的变化，的社会地位在不断变化。由于硬骨鱼特有的全基因组复制，拥有两个雄激素受体 (AR) 同源物，和 ，这为我们提供了一个独特的机会来区分基因复制在社会系统进化中的作用。在这里，我们使用 CRISPR/Cas9 基因编辑生成 AR 突变体 和进行了一系列实验来探究社会优势的机制基础。我们发现 但不是 ，对于睾丸生长和鲜艳的颜色是必需的，而 ，但不是 ，对于生殖行为和攻击行为的表现是必需的。两个受体都需要减少雌性的逃跑，而任何一个 AR 都足以攻击雄性。因此，在 中，社会地位高度可分离，并受两个 AR 同源物的模块控制。这种非冗余性可能对促进 以及其他依赖社会经验的物种的社会可塑性很重要。
