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Chloroplast DNA variation in the Quercus affinis – Q. laurina complex in Mexico: geographical structure and associations with nuclear and morphological variation
Author(s) -
GONZÁLEZRODRÍGUEZ A.,
BAIN J. F.,
GOLDEN J. L.,
OYAMA K.
Publication year - 2004
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2004.02344.x
Subject(s) - biology , chloroplast dna , haplotype , range (aeronautics) , restriction fragment length polymorphism , population , genetic variation , evolutionary biology , phylogeography , genetic diversity , ecology , genetics , chloroplast , polymerase chain reaction , phylogenetics , demography , genotype , materials science , sociology , gene , composite material
The geographical distribution of chloroplast DNA (cpDNA) variation in 39 populations of two hybridizing Mexican red oaks, Quercus affinis and Q. laurina , was investigated using polymerase chain reaction‐restriction fragment length polymorphism (PCR–RFLP). Six haplotypes were identified. Of these, two (H1 and H4), separated by four mutations, had high frequencies (58 and 23% of the individuals, respectively) and were present across the whole geographical range of both species, often co occurring in the same populations. The other four haplotypes were rare, geographically restricted, and are probably derived from the two frequent haplotypes. Latitudinal or other clinal patterns in diversity levels or haplotype composition of populations were not apparent. The pattern of haplotype distribution was characterized by some mosaicism, with contrasting populations often situated in proximity. Average within‐population diversity ( h S = 0.299) and population differentiation ( G ST = 0.499) were, respectively, higher and lower than values reported in previous studies of oak species. There was evidence for phylogeographical structure, as indicated by N ST (0.566) being significantly higher than G ST . Haplotypic variation was largely species‐independent, although some very weak associations were detected between haplotypes H1 and H4 and morphological and nuclear molecular variation correspondingly characterizing Q. affinis and Q . laurina . These oaks probably did not experience a marked restriction to one or a few particular subregions of their present range during the last glacial cycle. It is more likely that substantial populations persisted throughout several episodes of climatic change, but experienced recurrent latitudinal and altitudinal migrations which may have caused the widespread distribution of haplotypes H1 and H4 and frequent intermixing of populations.