Genetic diversity analysis by RAPD inCathaya argyrophylla Chun et Kuang

Genetic diversity level ofCathaya argyrophylla was confirmed by random amplified polymorphic DNA (RAPD) markers. Seventy five samples (individuals), collected from Hunan and Sichuan provinces of China were used in the study. 21 10-mer oligonucleotide primers detected 106 sites, and 34 (32%) of them were polymorphic. The level of genetic variation in C.argyrophylla was lower than those of other conifers, and was considered to be associated with the complexity of habitats. The percentages of polymorphic sites (PPS) in the Hunan and Sichuan populations were 18% and 25% respectively. 7.99% of genetic variation existed between the two populations; this value was higher than the mean value (6.8%) among populations in conifers displayed by allozyme. Some subpopulations ofC. argyrophylla were greatly differentiated because of site mutation and genetic drift. The highest value of genetic difference between subpopulations amounted to 16. 23%. In addition, a concept of diversity coefficient (DC), a value used to measure the genetic diversity level, and its calculation were proposed. The low genetic diversity level ofC. argyrophylla was thought to be one of the factors causing its endangered status.