Genetic diversity and population structure of critically endangered Dactylorhiza hatagirea (D. Don) Soo from North-Western Himalayas and implications for conservation

Abstract

Dactylorhiza hatagirea (D. Don) Soo is medicinally important herb, which is widely used in ayurveda, unani, and folk/traditional medicine system to cure diseases. Due to its immense ethno-botanical properties, the trade of D. hatagirea is estimated to be USD 1 billion/year in India. Unfortunately, due to overexploitation of the herb from the wild, has resulted in dwindling of its populations in their natural habitats, which has led to its critically endangered status. Molecular genetic studies are still scarce in D. hatagirea, therefore, in current study, genetic diversity and population structure analysis was carried out of 10 populations (48 individuals) collected from three cold desert regions (2527 m–3533 m amsl) of Himachal Pradesh. Mean observed heterozygosity (Ho) and expected heterozygosity (He) was recorded 0.185 and 0.158. The maximum values for Fst (fixation index) and Nm (gene flow) were recorded 0.945 at locus KSSR14 and 1.547 at locus KSSR 4 respectively. Mean genetic differentiation (Fst) coefficient was estimated to 0.542. Overall, low levels of genetic diversity was recorded in the populations of D. hatagirea, might be due to habitat specificity (alpine meadows ecosystem; humid laden undulating habitat), restricted distribution and high anthropogenic activities. However, two populations viz., Bathad and Rangrik were recorded with high diversity and largest number of private alleles, stipulates that these populations might have high evolutionary significance and response to selection. Dendrogram analysis revealed that the populations of D. hatagirea were clustered into four major clusters, which was supported by Bayesian based STRUCTURE predictions. Clustering pattern of majority individuals of different populations revealed consistency with their geographic origin. Outcomes of current study reveals the status of genetic diversity and population structure of endangered D. hatagirea, which can be futuristically utilised for appropriate planning of conservation strategies.