Comparative Mapping of the Muscadine Grape (Vitis rotundifolia) and the European Bunch Grape (V. vinifera) Shows a High Level of Synteny Between the Two Species

Vitis rotundifolia is one of about 60 wild Vitis species that is related to the primary cultivated grape species V. vinifera. To generate molecular resources for gene mapping and identification, a high-density genetic linkage map was constructed for V. rotundifolia using single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS) and evaluated in two F₁ populations.  Over 2,000 SNP markers were selected for analysis and segregated to form 20 linkage groups. The relationship between V. rotundifolia linkage groups and V. vinifera chromosomes was examined by aligning SNP-containing sequences from V. rotundifolia to the genome sequence of V. vinifera. A high degree of colinearity was observed between V. rotundifolia linkage groups and the V. vinifera reference genome. The primary difference between the two genomes appears to be the splitting of chromosome 7 into two separate linkage groups in V. rotundifolia, accounting for the increase in chromosome number of this species. The development of molecular resources for species closely related to V. vinifera provides information into the evolution of genomes within the genus Vitis and tools to help identify genes within this wild species that could be useful to grape breeding.