Molecular and evolutionary analysis of a plant Y chromosome

Plants have evolved a great diversity of sex determination systems. Among t hese, the XY system, also found in mammals, is one of the most exciting sin ce it gives the opportunity to compare the evolution of sex chromosomes in two different kingdoms. Whereas generic and molecular mechanisms controllin g sex determination in drosophila and mammals, have been well studied, very little is known about such processes in plants. White campion (Silene lati folia) is an example of plant with X and Y chromosomes. What is the origin of the X and Y chromosomes! How did they evolve from a pair of autosomes! I n our laboratory, we have isolated the first active genes located on a plan t Y chromosome. We are using them as markers to trace the origin and evolut ion of sex chromosomes in the Silene genus. (C) 2001 Academie des sciences/ Editions scientifiques et medicales Elsevier SAS.