Pervasive relaxed selection on spermatogenesis genes coincident with the evolution of polygyny in gorillas.

Relaxed purifying selection on 578 genes related to spermatogenesis coincides with the evolution of polygyny in gorillas, leading to reduced sperm quality.

• Why it matters: Understanding the genetic basis of reproductive traits helps explain how social systems influence fertility and can reveal causes of male infertility in humans, addressing a significant knowledge gap.
• What they did: The study analyzed 13,310 protein-coding genes across 261 mammals, identifying genes under relaxed selection in gorillas, and validated their roles using fruit fly models and human genetic data.
• The result: Findings show that relaxed selection has led to deleterious mutations in male reproductive genes, providing insights into gorilla low sperm quality and uncovering new candidate genes for human male infertility.