Chromosome Study on Different Geographical Populations of Yunnanites coriacea

Yunnanites coriacea was an endemic species of China. In order to understand the cytogenetic characteristics of different populations of Y.coriacea, the chromosome karyotype and C-band patterns of 2 geographic populations of Y.coriacea were studied by squashing and BSG chromosomal banding technique. The results showed that the 2 geographic populations had a diploid chromosome number of 2n (♂)=19 with a fundamental number (NF)=19, all chromosomes were telocentric and an XO sex-determining mechanism. The karyotype formula of Y.coriacea was 2n(♂)=3L + 6M + X, large and medium, and the X chromosome was the first element in size. The C-band karyotype analysis indicated that there were only 10 centromeric C-bands with a total of heterochromatic content (THC) was 10.67% in Kunming Western mountain population while the population in Dongchuan tuobuka had 10 centromeric C-bands and 8 terminal C-bands, and the total of heterochromatic content was 29.53%. Combining the external morphological differences of the 2 population, It could be considered as 2 different geographic subspecies.