Chloroplast DNA markers revealed a geographical divide across Argentinean southern beech Nothofagus nervosa (Phil.) Dim. et Mil. distribution area

MARCHELLI, P.; GALLO, L; SCHOLZ, F; ZIEGENHAGEN, B

THEORETICAL AND APPLIED GENETICS

Año: 1998 vol. 97 p. 642 - 646

0040-5752

Nothofagus nervosa is one of the most importantspecies of the temperate forests of southern SouthAmerica. On the eastern slope of the Andes Mountains(Argentina) it has a very small and narrow naturaldistribution area which follows the valleys of the numerouswest-east lake basins. Re-colonisation after thelast glaciation is assumed to have originated from refugialocated in the western paciÞc coast or even in freeinterglacial patches of the Andes Mountains. Sixteenpairs of primers were used to amplify 16 non-codingregions of chloroplast DNA in 11 populations fromover the entire distribution area in Argentina. Afterrestriction analysis two polymorphic fragments werefound which deÞned two haplotypes and allowed a differentiationamong populations. A clear geographicdivide occurs separating populations distributed southand north of a west-east mountain chain. This suggeststhat after the last glaciation the species spread out fromat least two di¤erent refugia. Hypotheses about thepossible location of these refugia are discussed.