Australia: The Land Where Time Began

A biography of the Australian continent 

Dictyostelium discoideum – Sex Determination in a Social Amoeba (slime mould)

In many organisms the genetics of sex determination has remained mysterious, even in some that have been in other ways well studied. In this paper Bloomfield et al. report the discovery and analysis of the mating-type locus in the model organism Dictyostelium discoideum. This species has 3 mating types, all of which are specified by forms of a single genetic locus: 2 versions of the locus differ entirely in sequence, the 3^rd resembling a composite of the other 2. Single genes that are unrelated are enough to determine 2 of the mating types, while the homologues of both these genes are required in the composite type. Polypeptides with no recognised similarity to established protein families are encoded by the key genes. It therefore appears that in social amoebae determination of sex uses regulators that are not related to any others that currently known.

Sources & Further reading

1. Bloomfield, G., J. Skelton, A. Ivens, Y. Tanaka and R. R. Kay (2010). "Sex Determination in the Social Amoeba Dictyostelium discoideum." Science 330(6010): 1533-1536.