WebSep 10, 2024 · Sex differences in lifespan remain an intriguing puzzle for evolutionary biologists. A possible explanation for lower lifespan in males is the unconditional expression of recessive deleterious alleles in heterogametic X chromosomes in males (the unguarded X hypothesis). Empirical evidence, however, has yielded controversial results that can be … WebMar 9, 2024 · The prevailing “unguarded-X” hypothesis (UXh) explains this by differential expression of recessive mutations in the X/Z chromosome of the heterogametic sex (e.g., females in birds and males in mammals), but has only received indirect support to date. An alternative hypothesis is that the accumulation of deleterious mutations and repetitive ...
Sex‐specific aging in animals: Perspective and future …
WebJun 1, 2016 · Here, we test a fundamental prediction of the unguarded X hypothesis: that the negative effect of inbreeding on lifespan should be more pronounced in the homogametic sex than in the heterogametic sex. This prediction arises because, in the heterogametic sex (e.g. males in XY systems and females in ZW systems), the sex chromosomes are always ... metformin and steroid injections
Genetic sex determination and sex-specific lifespan in ... - bioRxiv
WebMar 1, 2024 · A more explicit prediction made by the unguarded X hypothesis is that, during inbreeding, the homogametic sex should suffer a larger reduction in life span and in other traits under directional selection. This is because only the homogametic sex is affected by inbreeding of the X chromosome, while inbreeding of the autosomes affects both sexes. ... WebThe unguarded X hypothesis contends that dimorphic life spans arise from sex differences in X or Z chromosome copy number (i.e., one copy in the “heterogametic” sex; two copies … WebAug 22, 2024 · Researchers here discuss the unguarded X hypothesis in the context of gender differences in life span. That these differences exist across species strongly … metformin and statin combination