Sex determination and sex chromosome evolution in land plants
18 March 2022
The more or less sharp differen- tiation of male and female individuals, the genetics of sex, and the occurrence of the X/Y chromosome mechanism, [are] all parallel to conditions noted in angiosperms.’ The topic of sexual lability in dioecious species is taken up in this special issue by Käfer et al. [...] The small number of ZW systems in plants and the absence of any microscopically heteromorphic sex chromosomes in such systems so far preclude the detection of possible toxicity of W chromosomes. [...] In several of the taxa studied in this special issue, such as Ginkgo, Mercurialis and Populus, the non-recombining region with the sex-deter- mining genes is small, and this does not appear to relate to the age of the respective systems, although this is extremely difficult to infer . [...] (d) The identification of sex-determining genes and the molecular pathways connecting them to the formation of male and female floral structures Identifying the sex-determining genes is a key goal of sex chromosome research. [...] Despite the remarkable progress in the elucidation of plant sex-determining regions and genes, knowledge on the molecular mechanisms downstream of the sex determinants ultimately causing the differential development of female or male floral organs is lagging behind.