Amh/Amhr2 homologs: The predominant recurrent sex determining genes in teleosts
Year: 2025
Type: article
Abstract: Teleosts, the most diverse vertebrate group comprising over 30,000 species, exhibit the most complex sex determination systems and mechanisms among vertebrates. With the increasing availability of sequenced and assembled fish genomes, numerous sex-determining genes (SDGs) have been successfully identified. Despite the diversity of SDGs discovered in teleosts, members of the TGF-β superfamily are frequently and independently recruited as SDGs across divergent fish lineages. Of over 150 teleost species with identified SDGs, approximately 60 % have recruited TGF-β superfamily members as their SDGs. Within the species utilizing TGF-β members as SDGs, 85 % use homologs of anti-Müllerian hormone ( amh ) and its dedicated type II receptor ( amhr2 ) as SDGs. To date, 34 teleost species have been documented to utilize amh and 43 utilize amhr2 homologs as SDGs respectively. This selection bias underscores amh / amhr2 as the current 'star players' among identified teleost SDGs. However, the reasons behind the recurrent recruitment of amh / amhr2 as SDGs, along with their downstream signaling pathways and molecular mechanisms governing teleost sex determination, remain unclear. Here, we systematically summarize recent advances in understanding the recruitment of amh / amhr2 as SDGs in teleosts. We propose that this preference may stem from functional redundancy, single-copy genomic architecture, ligand-receptor binding specificity and high affinity regulatory capacity in germ cell proliferation, as well as differentiation and extensive crosstalk with downstream male and female sex determination pathways. Future research should focus on the following aspects: elucidating the specificity and conservation of components in the Amh/Amhr2 signaling pathway, systematically identifying its downstream target genes and regulatory networks, and thoroughly investigating the evolutionary driving mechanisms behind its frequent recruitment as SDG. This review enhances mechanistic insights into the repeated co-option of amh / amhr2 as SDGs and advances the exploration of their signaling cascades and molecular networks in teleost sex determination. • Reveals amh / amhr2 as the predominant recurrent SDGs in teleosts. • Advances hypotheses explaining the evolutionary bias toward amh / amhr2 as SDGs. • Highlights gaps in the molecular cascades and signaling networks of Amh/Amhr2-mediated sex determination.
Source: Water Biology and Security
Authors: Li Zhou, Deshou Wang, Xingyong Liu
Institution: Southwest University
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: diamond
Awards: G1126772301, G6428954503
OpenAlex ID: W7083588371