A Comparison of Chromosome Variability in Asarum asperum and A. hexalobum (Aristolochiaceae)

Abstract

Asarum asperum and A. hexalobum showed the common chromosome number of 2n=24 and quite similar karyotypes to each other. The two species displayed DAPI-positive and negative bands unstable in appearance and CMA-bands stable in appearance in the mitoticmetaphase chromosome complement. Thus, the present CMA-banding approach showed them to be separate species: Asarum asperum was characterized by only four CMA-bands; two positioned at the centromeric region of the 15th and the 16th homologous chromosomes and the other two positioned at the interstitial region of the short arm of the 23rd and the 24th homologous chromosomes. The latter CMA-bands performed either equal combination of two small-sized CMA-bands or unequal combination of small-sized and large-sized CMA-bands, which were depended on population. Asarum hexalobum was characterized by eight CMA-bands; six positioned at the centromeric region of the 11th and the 12th, the 15th and the 16th, and the 19th and the 20th homologous chromosomes and two positioned at the interstitial region of the short arm of the 23rd and the 24th homologous chromosomes.