On the cover: The presence of a heteromorphic Y chromosome defines males in the dioecious plant, Silene latifolia. Male plants with an X and a Y chromosome develop staminate flowers (wild type, left chromosomes and a lower left flower). In this issue, Koizumi et al. (pp. 1450-1461) isolated an asexual mutant, K034, in S. latifolia. K034 had two abnormal sexual phenotypes expressed as asexual and imperfect female (female-like) flowers. Most of K034 flowers were asexual flowers with rudimentary stamens and a suppressed gynoecium (K034, right chromosomes and a lower right flower). Female-like flowers of K034 had a slimmed ovary with one to three styles. K034 had three large sex chromosomes, two X chromosomes and one rearranged Y chromosome (Yd). PCR analysis using Y-specific STS markers clarified that Yd of K034 had two deletions in gynoecium-suppressing and stamenpromoting regions on the Y chromosome.
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