Tracing the origins of stocks of the endangered species Primula sieboldii using nuclear microsatellites and chloroplast DNA

We examined the origins of cultivated stocks of the endangered species Primula sieboldii at the individual plant level by using an assignment test based on eight microsatellite loci and regional features of chloroplast DNA (cpDNA) variation of wild populations. To confirm that we had sufficient information for estimating the origins of the stocks, we performed an assignment test with 920 genets that we collected from 32 wild populations with known origins. The test assigned 99.6% of the genets to the population from which they had been sampled, confirming the suitability of the method. We then performed the assignment test with 29 cultivated stocks. The alleged origins of 19 were confirmed by microsatellite and cpDNA variations. In contrast, the alleged origins of five were rejected by both markers. Five stocks, which do not have a reference population located within 30 km of their reputed origin, were not assigned to any population. Stocks whose alleged origins were rejected are inappropriate as restoration materials, because their introduction might disturb local gene pools. Six stock haplotypes could not be detected in wild populations. This may suggest the loss of genetic diversity in the wild and the value of stocks as a gene bank. The genetic method used in this study will also be helpful to detect cryptic invasion by nonendemic genotypes or to trace the origins of plants collected for commercial purposes, a threat to many endangered species.