A novel RFLP linkage map from an F2
--M. Enrico Pè, Raffaella Greco, Graziana Taramino, Luca Gianfranceschi, Renato Tarchini and Giorgio Binelli

We present here the linkage data from the analysis of 150 plants of an F2 generation obtained from inbreds B89 and 33-16. The RFLP clones used were from Pioneer Hi-Bred Intl. (pio), Brookhaven Natl. Lab. (bnl) and University of Missouri-Columbia (umc). A total of 160 have been screened on the parents to detect polymorphism using EcoRI, BamHI and HindIII as restriction enzymes. 95 polymorphic clones have been chosen to be used for the F2 characterization, trying to avoid overlapping or too large intervals between the clones. 10 RAPD markers (commercially available 10-mers from Operon Technologies) have also been used. The estimate of recombination frequencies and the determination of linkage groups were performed by MAPMAKER. The order and the distance between markers are in accordance with the published maps, with some exception: pio200668 (on chromosome 1, in our map on chromosome 2), umc36 (7,2), umc93 (8,2), umc49 (2,4), pio200608 (4,6), umc111 (4,7), bnl6.25 (5,8), bnl5.62 (1,8). Chromosome 2 is split into two groups, due to the presence of a large region where we could not find polymorphic markers. The total genetic distance spanned by our markers is 1539cM (Kosambi's function), with an average distance between clones of 14.5cM. The original data set of the molecular typing of the F2 is available upon request.

Figure 1. RFLP and RAPD linkage map of maize, based on recombination data from an F2 generation of 150 plants. Genetic distances are in cM (Kosambi's function).  1&2, 3&4, 5&6, 7&8, 9&10.

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