XB-FEAT-18006528

dmw

This is the community wiki page for the gene 'dmw' please feel free to add any information that is relevant to this gene that is not already captured elsewhere in Xenbase.

gene function

The dm-w gene is purported to be involved in sex determination in amphibians, and is related to (thus is a paralog of ) the DMRT1 gene family which are sex determining genes in reptiles. In X. tropicalis, a diploid ( 2N=20) species, sex determination has been investigated by Monica Bullejos at the Universiidad de Jaen,Spain, Bene Evans, Amy Sater, Marko Horb and others. .

Bullejos used cytogenetic analysis to look for sex determining genes at chromosomes at metaphase, but could not see any difference between X. laevis and X. tropicalis. Chemical induced sex reversal experiments in X. tropicalis determined that the sex determining system is a YW/YZ.

See The review/overview from Schartl 2015 https://doi.org/10.1073/pnas.151351811 and Roco et al 2015 https://doi.org/10.1073/pnas.1505291112

Roco et al 2015 demonstrated the Xtrop does not have the dm-w gene at all. Their “analysis shows that both males and females in X. tropicalis can be either homogametic or heterogametic. At least three different types of sex chromosomes exist: Y, W, and Z, observed in YZ, YW, and ZZ males and ZW and WW females. “

Again Roco et al 2015 described 3 different types of sex chromosomes exist: Y, W, and Z, observed in YZ, YW, and ZZ males and in ZW and WW females.

And they said that “Genetic markers linked to the X. tropicalis sex-determining locus were identified in an amplified fragment-length polymorphism study (35). These markers largely place to sequence scaffolds that genetically map to the short arm of linkage group 7 (chromosome 7).” 

Hayashi et al 2023, published a paper about the promoter regions for dm-w in Xenopus and they also concur- no dm-w in X. tropicalis: [[1]]

So of the 3 sex 'genes'/chromosomes, Y W and Z, it has been shown that the a dominance hierarchy exists: Y > W > Z.

Wells et al 2011, (Development) found that sex 'chromosomes' Y and W have not accumaulated deleterious mutations. They also that's that the sex determining genes are on Chromosome 7.