Labonne, Jonathan , Shore, Joel .
High-resolution mapping of the S-locus in distylous Turnera.
As a prelude to discovery of genes involved in floral dimorphism and incompatibility, a genetic map of distylous Turnera was constructed coupled with a high-resolution map of the S-locus region. The genetic map consists of 79 PCR-based molecular markers (48 AFLP, 18 RAPD, 9 ISSR, 4 RAMP), 5 isozyme loci, one additional gene and the S-locus spanning a total distance of 683.3 cM. The 86 markers were distributed in five linkage groups corresponding to the haploid chromosome number. Five molecular markers (1 RAPD, 1 ISSR, 3 RAMP) showing tight linkage with the S-locus in an initial mapping population of 94 individuals were cloned and sequenced to determine whether they correspond to genes. The RAPD marker OPK14c has similarity to a steroid/flavonol sulfotransferase while the ISSR marker IS864a and RAMP marker RP81E18 showed similarity to an N-acetlytransferase and a retrotransposon, respectively. To determine the degree of linkage of the three genes with the S-locus, further crosses were made and an additional 1919 progeny was produced. Assaying of the additional progeny for the three genes and two molecular markers allowed the construction of a high-resolution map of the S-locus region. The map consists of two markers (N-acetyltransferase and RP45E9) flanking the S-locus at distances 0.35 and 0.84 cM, respectively, and three additional markers (sulfotransferase, retrotransposon and RP45G18) co-segregating with the S-locus in a total mapping population of 2013 individuals. A Bacterial Artificial Chromosome (BAC) library of T. subulata has been constructed and markers of the high-resolution map are being used initiate chromosome walking in order to find the genes residing at the S-locus.
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1 - York University, Department of Biology, 4700 Keele street, Toronto, Ontario, M3J1P3, Canada
2 - York University, Department of Biology, 4700 Keele St, Toronto, Ontario, M3J 1P3, Canada
Presentation Type: Oral Paper:Papers for Sections
Location: 182/I K Barber
Date: Monday, July 28th, 2008
Time: 10:15 AM