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    Mexican spruce (Picea mexicana Martínez), an endangered species of the highest sky islands in México’s Sierra Madre Oriental and Sierra Madre Occidental, is threatened by fire, grazing, and global warming. Its conservation depends on whether it also is threatened by inbreeding and loss of genic diversity. We used 18 isozyme markers in 12 enzyme systems to assay genic diversity, characterize the mating system, and test for recent bottlenecks in three known populations. Unbiased, expected heterozygosity (He) averaged 0.125. Despite a separation of 676 km between populations in the Sierra Madre Oriental and the Sierra Madre Occidental,Wright’s FST, the proportion of total genic diversity among populations, was only 6.9%. Nei’s genetic distance was 0.001 between the populations in the Sierra Madre Oriental and more than an order of magnitude greater, 0.019, between the Sierra Madre Oriental and Sierra Madre Occidental.

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    Ledig, F. Thomas; Hodgskiss, Paul D.; Jacob-Cervantes, Virginia. 2002. Genetic diversity, mating system, and conservation of a Mexican subalpine relict, Picea mexicana Martínez. Conservation Genetics 3:113-122


    Bottlenecks, endangered species, fragmentation, global warming, isozymes

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