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...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-βsuperfamily are frequently and independently recruited as SDGs across divergent fish lineages.Of over 150 teleost species with identified SDGs,approximately 60%have recruited TGF-βsuperfamily members as their SDGs.Within the species utilizing TGF-βmembers 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.展开更多
Backgroud:Persistent Müllerian duct syndrome(PMDS)is a rare condition characterized by the persistence of Müllerian duct structures in genotypic and phenotypic males.Case Presentation:We present the case of ...Backgroud:Persistent Müllerian duct syndrome(PMDS)is a rare condition characterized by the persistence of Müllerian duct structures in genotypic and phenotypic males.Case Presentation:We present the case of a 4‐month‐old male with PMDS who presented with transverse testicular ectopia.The patient underwent diagnostic laparoscopic orchiopexy with preservation of the Müllerian structures to maintain future fertility options.Due to the abnormal appearance of the testes,a biopsy revealed normal testis tissue without any ovarian tissue.Genetic testing identified a unique mutation in each copy of the AMHR2 gene:c.322A>C and c.658G>C.Neither mutation has been previously reported.Conclusion:This case highlights the importance of considering PMDS in male infants presenting with transverse testicular ectopia.Early recognition and fertility‐preserving surgical management are essential,and novel genetic variants continue to expand the mutational spectrum of AMHR2‐related PMDS.展开更多
基金supported by the National Key Research and Development Program of China[grant number 2022YFD1201603]the National Natural Science Foundation of China[grant number 31861123001]Chongqing Fishery Technology Innovation Union[grant number CQFTIU202501-07].
文摘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-βsuperfamily are frequently and independently recruited as SDGs across divergent fish lineages.Of over 150 teleost species with identified SDGs,approximately 60%have recruited TGF-βsuperfamily members as their SDGs.Within the species utilizing TGF-βmembers 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.
文摘Backgroud:Persistent Müllerian duct syndrome(PMDS)is a rare condition characterized by the persistence of Müllerian duct structures in genotypic and phenotypic males.Case Presentation:We present the case of a 4‐month‐old male with PMDS who presented with transverse testicular ectopia.The patient underwent diagnostic laparoscopic orchiopexy with preservation of the Müllerian structures to maintain future fertility options.Due to the abnormal appearance of the testes,a biopsy revealed normal testis tissue without any ovarian tissue.Genetic testing identified a unique mutation in each copy of the AMHR2 gene:c.322A>C and c.658G>C.Neither mutation has been previously reported.Conclusion:This case highlights the importance of considering PMDS in male infants presenting with transverse testicular ectopia.Early recognition and fertility‐preserving surgical management are essential,and novel genetic variants continue to expand the mutational spectrum of AMHR2‐related PMDS.
