Mitosis-meiosis transition, the regulation of the means to sexual reproduction

摘要

Reduction of chromosome number through meiosis is a central event that facilitates sexual reproduction in eukaryotes. In addition to providing an opportunity for genetic reassortment, it makes the transition from diploid somatic to haploid gametic phase. Whereas cellular differentiation is established during initial stages of development in animal systems, no true germline is set aside in early embryogenesis in plants, where both vegetative and generative parts are derived from meristems during growth and differentiation. As such, the regulation of mitotic to meiotic transition is the most vital event in the life of a plant. Although, the basic control mechanisms that strictly regulate cyclin-dependent kinases for temporal progression through the cell cycle are remarkably well understoodTM, no definite information on molecular identity of signals that regulate the switch from mitosis to meiosis is yet available. Lately, some data on the development of cell lineage involved in these events are beginning to emerge5.