| Achoimre: | <p>Sex chromosomes in plants have been known for a century, but only recently have we begun to understand the mechanisms behind sex determination in dioecious plants. Here, we discuss evolution of sex determination, focusing on <em>Silene latifolia</em>, where evolution of separate sexes is consistent with the classic “two mutations” model—a loss of function male sterility mutation and a gain of function gynoecium suppression mutation, which turned an ancestral hermaphroditic population into separate males and females. Interestingly, the gynoecium suppression function in <em>S. latifolia</em> evolved via loss of function in at least two sex-linked genes and works via gene dosage balance between sex-linked, and autosomal genes. This system resembles X/A-ratio-based sex determination systems in <em>Drosophila</em> and <em>Rumex</em>, and could represent a steppingstone in the evolution of X/A-ratio-based sex determination from an active Y system.</p>
|
|---|