INDISTINGUISHABLE PATTERNS OF RECOMBINATION RESULTING FROM MATE AND FEMALE MEIOSES IN BRASSICA-NAPUS (OILSEED RAPE)

An F-1 individual derived from a cross between two distinct lines of s pring oilseed rape (Brassica napus) was used to produce a pair of comp lementary backcross populations, each consisting of 90 individuals. Th e F-1 donated male gametes to the Male population and female gametes t o the Female population. Genetic maps were generated from both populat ions and aligned using 117 common loci to farm an integrated genome ma p of B. napus with 243 RFLP-defined loci. A comparison of the frequenc y and distribution of crossovers in the two populations of F-1 gametes (assayed in the Male and Female populations) detected no differences. The genetic maps derived from the Male and Female populations each co nsisted of 19 linkage groups spanning 1544 and 1577 cM, respectively. The maps were aligned with other B. napus maps, and all 19 equivalent linkage groups were unambiguously assigned. The genetic size and gener al organisation of the new maps were comparable with those of pre-exis ting B. napus maps in most respects, except that the levels of polymor phism in the constituent A and C genomes were unusually similar in the new cross.