In other species: goldfish , common carp , suckers , northern pike , rainbow trout , Atlantic salmon , European hake , guppy , Nile tilapia , Pacific bluefin tuna , Japanese flounder , Atlantic halibut , Gila monster , monocled cobra , emu , Mallard , swan goose , Canada goose , chicken , common quail , turkey , platypus , Australian echidna , spotted hyena , Asiatic elephant , African Elephant , ass (donkey) , domestic horse , taurine cattle , sheep , Chinese soft-shelled turtle , jackdaw , petrels , torafugu , whitespotted clarias , red-eared slider turtle , flathead mullet , ayu , Wuchang bream , water buffalo , Japanese quail , central bearded dragon , silver arawana , Chinese spiny frog , Greenland flounder , mandarin fish , green-eyed treefrog , barred knifejaw , derbio , Inca scad , northern snakehead , golden trevally , twoband anemonefish , Java barb , clearhead icefish , Okinawa island spiny rat , Guenther's mouthbrooder , short-snouted icefish , silver trevally

Categories: Reproductive system phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 261550 (trait) , 600956 (gene)

Single-gene trait/disorder: unknown

Disease-related: no

Species summary: [IT thanks Emma Faull for contributions to this entry in September 2025]  

Molecular basis: The development of the scrotum and the mammary primordia are “under the direct genetic control of a gene or genes on the X-chromosome” (Renfree and Shaw, 2023), with the “occurrence of a pouch and mammary glands, or a scrotum” related to “the number of X chromosomes, rather than the presence or absence of a Y chromosome” (Glickerman et al., 2005). Renfree and Shaw (2023) further investigated the “expression of the genes responsible for phallus differentiation, notably SHH” and found that “SHH, along with Gli2 and AR were markedly upregulated in the urethral epithelium at day 50 pp, a time when testicular androgens are falling. These genes were downregulated in female pouch young treated with adiol from day 24 to day 50 but not when treatments were begun at day 29, suggesting an early window of androgen sensitivity. SHH, GLI2 and AR expression in the phallus of males castrated at day 23 did not differ from controls, but there was an increase in SHH and GLI2 and a decrease in FGF8 and BMP4 expression when the animals were castrated on day 29. These results suggest that an androgen-dependent window of sensitivity between about days 24 and 50 regulates later SHH expression in the developing male phallus … Genes encoding the 3α-reductases, AKRIC2 and AKRIC3, produce alloprenanolone only by the alternate pathway, and mutations in AKRIC2 and aberrant splicing of AKRIC3 explain some DSDs in 46,XY individuals.” Whitworth et al. (2001) details another gene, SF1, which “is expressed by both the developing tammar testis and ovary before, and throughout, the period of sexual differentiation which is consistent with a role in gonadal development but is not supportive of a role in testicular differentiation … SF1 transcripts are also present in adult testis and ovary where it is likely required for steroidogenesis”.