AFLP Analysis of Gene Pools of a Wild Bean Core Collection

Abstract

Studies of diversity permit conclusions about the genetic structure of species. Systematically developed core collections are a particularly good tool for such purposes. The objective of this study was to evaluate the genetic structure between and within gene pools of a core collection of wild Phaseolus vulgaris L. using the technique of amplified restriction polymorphism (AFLP) analysis. DNA fingerprint patterns of 114 genotypes were analyzed by the NTSYS program. Major groups or gene pools were recognized in Mesoamerica, Colombia, the northern Andes of Ecuador and northern Peru, and the southern Andes, although the separation among gene pools was not wide. A unique segment of germplasm from northern Peru showed greater genetic distance than the other gene pools. Although most Mexican wild beans formed a rather homogenous group, a small number of accessions clustered with the Andean gene pool, and accessions from Guatemala tended to cluster apart from Mexican accessions. In the southern Andean gene pool, more discrete groups were formed which were associated with certain regions such as Argentina, possibly reflecting greater geographic and genetic isolation. Colombian accessions appeared to be highly introgressed with germplasm from other areas. AFLP analysis produced a large amount of data in a short period, thus permitting greater insights into the genetic structure of wild beans than had been possible with other methods of analysis.

Investigation of the domestication of common bean (Phaseolus vulgaris) using multilocus sequence data

“…Typically, during domestication, important agronomic characters are selected which result in a genome-wide reduction of genetic diversity in the domesticates (Tanksley and McCouch 1997;Eyre-Walker et al 1998;Buckler et al 2001;Diamond 2002;Clark et al 2004;Papa et al 2007, Pozzi et al 2004Otero-Arnaiz et al 2005;Vasemagi et al 2005;Doebley et al 2006;Kilian et al 2007;Zhu et al 2007). Earlier studies in bean using DNA marker, protein and morphological variation, determined that domesticated landraces indeed contain a subset of the variability found in wild beans Debouck et al 1993;Kami et al 1995;Tohme et al 1996;Beebe et al 2001;Chacón et al 2005). Here we observed that the amount of variability/polymorphisms retained is similar to the diversity estimates found in wild types.…”

“…Two large gene pools of wild types were identified based on phaseolin seed protein variation Gepts 1990), DNA marker diversity (Becerra Velasquez and Gepts 1994;Sonnante et al 1994;Freyre et al 1996;Tohme et al 1996), morphology (Evans 1976;Gepts and Debouck 1991), isozymes (Koenig and Gepts 1989), mitochondrial DNA variation (Khairallah et al 1992) and amplified fragment length polymorphism (AFLP) (Rossi et al 2009) and short sequence repeats (SSR) ) marker data.…”

Why not beans?

“…Common beans have exceptionally wide genetic variation among four gene pools and many races (Tohme et al 1996;Beebe et al 2001) two of which form the focus of sequencing work performed by Mamidi et al (2011). Reflecting this diversity, the CIAT maintains a primary gene bank with more than 36 000 accessions providing raw material for improving the crop using traditional breeding and molecular marker approaches.…”

Caracterização da diversidade genética em feijão por meio de marcadores RAPD

“…Polimorfismos de DNA amplificado ao acaso (RAPD), assim como outros marcadores de DNA, como RFLP (polimorfismos de comprimento de fragmentos de restrição) e AFLP (polimorfismos de comprimento de fragmentos amplificados) têm sido utilizados para medir a diversidade genética entre e dentro de espécies de microrganismos e plantas, incluindo o feijoeiro (Berkum et al, 1996;Tohme et al, 1996;Vasconcelos et al, 1996). Marcadores RAPD, pela sua simplicidade técnica e capacidade em detectar diferenças entre genótipos relacionados, são mais utilizados.…”