Genetic structure of the endangered Leucomeris decora (Asteraceae) in China inferred from chloroplast and nuclear DNA markers

Abstract

The genetic variation and structure of Leucomeris decora, an endangered species in China were investigated. Analyses of three chloroplast DNA (cpDNA) regions (the rpl16 intron, trnQ-5′rps16 intergenic spacer and rpl32-trnL intergenic spacer) and one nuclear gene (GAPDH: encoding glyceraldehyde 3-phosphate dehydrogenase) were conducted on 11 L. decora populations. Low levels of cpDNA genetic diversity were found in this species and within populations, with the identification of 2 haplotypes in a total of 2,745 bp, while the level of genetic diversity revealed by the nuclear gene GAPDH was relatively high, indicating that random losses of genetic polymorphisms from populations may have occurred recently. High levels of genetic differentiation among populations for both markers were detected in L. decora, which could be a consequence of the limited gene flow caused by geographic isolation among populations. An analysis of molecular variance revealed at the nuclear locus suggested the presence of geographic structure within the haplotype distribution possibly due to geographical barriers among populations. The haplotype network and mismatch distribution analyses did not detect the signal for a recent population expansion in L. decora. L. decora may persist in situ during climatic oscillations. Based on the genetic diversity and uniqueness of the populations, conservation strategies are discussed for this endangered species.