Early events in the evolution of the Silene latifolia Y chromosome: male specialization and recombination arrest.
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 Y p arm containing the putative stamen promoting sex determination locus includes additional early stamen developmental factors. A medial region of the Y q arm 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.
Zluvova
Jitka
J
Department of Plant Developmental Genetics, Institute of Biophysics of the Academy of Sciences of the Czech Republic, 612 65 Brno, Czech Republic.
Georgiev
Sevdalin
S
Janousek
Bohuslav
B
Charlesworth
Deborah
D
Vyskot
Boris
B
Negrutiu
Ioan
I
D005075:Biological Evolution; D018744:DNA, Plant / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics*; D014644:Genetic Variation; D009154:Mutation; D011995:Recombination, Genetic; D012098:Reproduction / Q000235:genetics*; D012641:Selection, Genetic; D012730:Sex Chromosomes / Q000235:genetics*; D029751:Silene / Q000235:genetics*; D013045:Species Specificity
D018744:DNA, Plant