ABSTRACT
The domestication process of the common bean gave rise to six different races which come from the two ancestral genetic pools, the Mesoamerican (Durango, Jalisco, and Mesoamerica races) and the Andean (New Granada, Peru, and Chile races). In this study, a collection of 281 common bean landraces from Chile was analyzed using a 12K-SNP microarray. Additionally, 401 accessions representing the rest of the five common bean races were analyzed. A total of 2543 SNPs allowed us to differentiate a genetic group of 165 accessions that corresponds to the race Chile, 90 of which were classified as pure accessions, such as the bean types 'Tórtola', 'Sapito', 'Coscorrón', and 'Frutilla'. Our genetic analysis indicates that the race Chile has a close relationship with accessions from Argentina, suggesting that nomadic ancestral peoples introduced the bean seed to Chile. Previous archaeological and genetic studies support this hypothesis. Additionally, the low genetic diversity (π = 0.053; uHe = 0.53) and the negative value of Tajima' D (D = -1.371) indicate that the race Chile suffered a bottleneck and a selective sweep after its introduction, supporting the hypothesis that a small group of Argentine bean genotypes led to the race Chile. A total of 235 genes were identified within haplotype blocks detected exclusively in the race Chile, most of them involved in signal transduction, supporting the hypothesis that intracellular signaling pathways play a fundamental role in the adaptation of organisms to changes in the environment. To date, our findings are the most complete investigation associated with the origin of the race Chile of common bean.
Subject(s)
Phaseolus , Phaseolus/genetics , Chile , Argentina , Domestication , Gene PoolABSTRACT
BACKGROUND: Polymorphic microsatellite markers were developed for Gaultheria pumila (Ericaceae) to evaluate genetic diversity and population structure within its native range in Chile. This is a very important Ericaceae endemic to Chile with a large commercial potential. Its resistance to different abiotic conditions makes it a valuable target for genetic improvement. RESULTS: Ten polymorphic simple sequence repeat (SSR) loci were isolated from Gaultheria pumila using new-generation 454 FLX Titanium pyrosequencing technology. The mean number of alleles per locus ranged from 2 to 4. Observed and expected heterozygosity ranged from 0.00 to 1.0 and 0.00 to 0.64, respectively. CONCLUSIONS: From 10 SSR markers developed for G. pumila, 9 markers are promising candidates for analyzing genetic variation within or between natural populations of G. pumila and other species from the same genus.