Adaptive genetic diversity and population structure of the "algarrobo" [Prosopis chilensis

L. I. FERREYRA; J. VILARDI; D. TOSTO; N. JULIO; B. SAIDMAN

EUROPEAN JOURNAL OF FOREST RESEARCH

Springer

Lugar: Freising ; Año: 2010 p. 1011 - 1025

1612-4677

The "algarrobo" [Prosopis chilensis (Molina) Stuntz] is a tree species that represents an important natural resource in arid and semi-arid regions of Argentina. In this paper we analysed and compared the variability of 46 RAPD (Random Amplified Polymorphic DNA) loci with previous estimates obtained from 12 isozyme markers in nine Argentinean populations of P. chilensis representative of the whole range of this species in Argentina. We evaluated the population structure and the existence of genetic variants associated to environmental variables. Expected heterozygosity (He) estimated from RAPD varied significantly among populations and regions. Hierarchical analysis of genetic variability (AMOVA) showed that most (88.1%) of total diversity occurs within populations, the component among populations within regions (9.3%) was intermediate, while the between region component was the lowest (2.6%). All three variance components were highly significant. The MDS plot from pair-wise ÖST matrix was consistent with the highly significant among region differentiation indicated by the AMOVA. All 12 variable isozyme loci and 26 out of 46 RAPD loci showed significant or highly significant association with at least one geographic/climatic variable according to the stepwise multiple regression analysis. These results imply that the genetic differentiation among populations is best explained by environmental or biogeographical grounds than by geographical distances, suggesting gametic disequilibrium with loci responsible for the adaptation to particular environmental conditions. The information from RAPD markers would provide a relevant criterion to preserve genetic diversity in programs for conservation and rationale use of this species.wise ÖST matrix was consistent with the highly significant among region differentiation indicated by the AMOVA. All 12 variable isozyme loci and 26 out of 46 RAPD loci showed significant or highly significant association with at least one geographic/climatic variable according to the stepwise multiple regression analysis. These results imply that the genetic differentiation among populations is best explained by environmental or biogeographical grounds than by geographical distances, suggesting gametic disequilibrium with loci responsible for the adaptation to particular environmental conditions. The information from RAPD markers would provide a relevant criterion to preserve genetic diversity in programs for conservation and rationale use of this species.