Toward the deciphering of chromosome structure in Vitis vinifera
Résumé
In the context of the sequencing project for the grapevine reference genome sequence, two genetic maps were completed with SSR markers in order to align the sequence contigs of the Vv12X.0 version of the genome assembly along the chromosomes. For this purpose, two full-sib families, 'Syrah' x 'Grenache' (SxG, 192 individuals) and 'Chardonnay' x 'Bianca' (CxB, 358 individuals) were respectively scored with 223 and 401 SSR. These two maps, supplemented with former data, allowed anchoring over 90% of the reference genome sequence. SNP markers were then defined from 37 anchored but not oriented and 44 not oriented and not anchored scaffolds of sequence. So far 110 new markers have been mapped, allowing anchoring 31 not yet anchored scaffolds (similar to 9 Mb) and orienting 35 scaffolds (similar to 15.5 Mb). In parallel, the recombination rate along the chromosomes is under study, in relation with sequence features (gene/repeat density, %GC, distance to the centromere/telomere). Finally, we are developing a cytogenetic map in Vitis vinifera using BAC-FISH. All these approaches will be combined to study the structure of the Vitis vinifera genome, including the factors affecting recombination rates and the dynamics of the genome evolution.