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High population differentiation and genetic variation in the endangered Mexican pine Pinus Rzedowskii (Pinaceae)
Author(s) -
Delgado Patricia,
Pin~ero Daniel,
Chaos Alvaro,
Pe´rezNasser Nidia,
AlvarezBuylla Elena R.
Publication year - 1999
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2656576
Subject(s) - biology , genetic variation , gene flow , inbreeding , population , endangered species , genetic structure , isolation by distance , evolutionary biology , genetic distance , pinaceae , conservation genetics , ecology , zoology , botany , allele , pinus <genus> , genetics , microsatellite , demography , habitat , gene , sociology
Pinus rzedowskii is an endangered pine species from Michoaca´n (central Me´xico), which has been previously reported from only three localities. Classified within the subgenus Strobus , it exhibits intermediate morphological characters between subgenera Strobus and Pinus . We analyzed genetic aspects that could shed light on the evolution and conservation of this species. The genetic structure of nine populations was examined using 14 isozyme loci. Pinus rzedowskii has a relatively high level of genetic variation with 46.8% of the loci assayed being polymorphic, a total of 35 alleles, and a mean heterozygosity per population of 0.219. We calculated Wright's F ST statistic to estimate gene flow indirectly and to evaluate whether or not there was genetic structuring among populations. We found a marked differentiation among populations ( F ST = 0.175) and significant inbreeding ( F IS = 0.247). No pattern of isolation by distance was found. We also constructed a dendrogram based on a genetic distance matrix to obtain an overview of the possible historical relationships among populations. Finally, we found a convex relationship between the genetic distance among populations and the number of ancestral lineages, suggesting that demographically this species has not been at risk recently. Although endangered, with small and fragmented populations, P. rzedowskii shows higher levels of genetic variation than other conifer species with larger populations or similar conservation status.