Genomic DNA polymorphism in <i>Myrica gale</i> (Myricaceae) in the Lebyazhiy state Nature Reserve (the southern coast of the gulf of Finland)

Abstract

The analysis of genomic DNA polymorphism is one of widely used approaches for studying the genetic structure of natural populations. It has been successfully applied to various plants. However, many species have not yet been studied, which is primarily due to methodological difficulties in isolating well-purified and non-degraded genomic DNA. These difficulties are due to the fact that plants possess numerous bioorganic compounds (polysaccharides, polyphenols, lipids, etc.) that contaminate DNA and significantly reduce its quality. Such species include marsh waxweed (Myrica gale L.), a perennial sub-Atlantic shrub with presumably vegetative propagation (in nature, waxweed seedlings are quite rare). We developed a simple protocol for isolation of high-quality genomic DNA from waxweed leaves and performed AFLP analysis of 42 plants of this species from three subpopulations in the Lebyazhiy Nature Reserve. Using three primer pairs, we isolated 22 amplification fragments, 8 of which were monomorphic. For the remaining 14 fragments, the average level of their polymorphism was low: depending on the subpopulation studied, it varied from 0.079 to 0.129. As shown by our analysis, all three studied subpopulations are polymorphic with a predominance of two common AFLP-genotypes. The corresponding plants are apparently the vegetative descendants of the founders. The rare AFLP-genotypes (represented by just one or two plants; a total of 12 such genotypes were identified) are likely the result of mutational and recombination processes. Our data give evidence that in the life cycle and dispersal of waxweed, the role of sexual reproduction is also noticeable.