A genetic basis for variations in meiotic recombination in Petunia hybrida

Abstract

Experimental data show that the meiotic recombination rate during female gametogenesis is controlled by one major nuclear factor, symbolized by Rm1, i.e., recombination modulator 1. The existence of modifiers, suggested by several data, remains to be demonstrated. Rm1 has been located on chromosome II by linkage with locus lu1. The regulation exerted by Rm1 is not directed only to a particular chromosome, but is more general. The recombination rate increases considerably for pairs of closely linked genes on chromosomes I, II, V, VI, and VII; it remains unchanged for a pair of weakly linked genes on chromosomes IV and decreases for a pair of moderately linked genes on chromosome III. Rm1 affects recombination in both male and female gametogeneses, but the effects differ in the two. The marked regions on chromosome III and VII were equally affected in male and female meioses, but the marked regions on chromosome II and VI were unaffected in male meiosis.Key words: Petunia hybrida, recombination, meiosis.