Genetic relationship among Eurasian and American Larix species based on allozymes

Abstract

Genetic variation at 16 allozyme loci was studied in both American (Larix occidentalis Nutt., L. laricina (Du Roi) C. Koch, L. lyallii Parl.) and Eurasian (L. sibirica Ledeb., L. gmelinii Rupr., L. olgensis A. Henry, L. kaempferi (Lamb.) Carr. (= L. leptolepis (Sieb. et Zucc.) Endl.), L. kamtschatica (Rupr.) Carr. and L. decidua (Mill.)) larch species. Species with a limited range, such as L. olgensis and L. lyallii, had lower genetic variation than species with a wider range. Population differentiation within species was of the same order of magnitude among species. The resulting phylogeny indicates a clear separation between American and Eurasian species. This result is in agreement with recent palaeontological findings that suggest that gene flow between American and Eurasian species has been unlikely since the last glaciation.