Insights on the Origin of Cultivated Potatoes

Several hypotheses have been postulated about the wild species that probably gave rise to cultivated potato species. Some of them have been evaluated, using molecular approaches and have received some support. Unfortunately, these studies have been done with a limited number of species and/or representatives of species, which limits the acceptance of their findings. We are using Genotyping by Sequencing (GbS) to generate Single-Nucleotide Polymorphims (SNP) marker data for 600 potato genotypes (360 wild and 240 cultivated). Using the GbS data already generated, phylogenetic analysis was performed to elucidate the most probable wild ancestors of the diploid cultivated potatoes. Cultivated diploid potatoes used in this study grouped together with representatives of wild species accessions of Solanum bukasovii, S. candolleanum and S. ambosinum, species now considered within S. candolleanum. Therefore, our results support the origin of the diploid cultivated potatoes from wild ancestors related to the present day wild species S. candolleanum. To confirm our findings, the number of accessions and genotypes of the three diploid species suggested as potential ancestors of the cultivated potato is currently being expanded and also accessions from polypoid species are being included. We are also investigating the best methodologies of GbS data analysis for potatoes. Optimizations of the workflow have been conducted first to improve the variant calling algorithms to facilitate the detection of genetic markers in an easy and reliable way. The ease-of-use of our method is constituted by the use of Galaxy and CloudMan, offering an intuitive interface on a cloud computing framework.