Early events in the evolution of the Silene latifolia Y chromosome: Male specialization and recombination arrest

Publikace: GENETICS 177, 375-386 Autoři: Zluvova, J., Georgiev, S., Janousek, B., Charlesworth, D., Vyskot, B., Negrutiu, L. Rok: 2007

Abstrakt

Understanding the origin and evolution of sex chromosomes requires studying recently evolved X-Y chromosome systems such as those in some flowering plants. We describe Y chromosome deletion mutants of Silene latifolia, a dioecious plant with heteromorphic sex chromosomes. The combination of results from new and previously described deletions with histological descriptions of their stamen development defects indicates the presence of two distinct Y regions containing loci with indispensable roles in male reproduction. We determined their positions relative to the two main sex determination functions (female suppressing and the other male promoting). A region proximal to the centromere on the Yparm containing the putative stamen promoting sex determination locus includes additional early stamen developmental factors. A medial region of the Yqarm carries late pollen fertility factors. Cytological analysis of meiotic X-Y pairing in one of the male-sterile mutants indicates that the Y carries sequences or functions specifically affecting sex chromosome pairing.