Comparative Cytogenetic Characteristics and Physical Mapping of the 17S and 5S Ribosomal DNAs between Atractylodes japonica Koidz. and Atractylodes macrocephala Koidz.

Abstract

This study was carried out to compare chromosomal characteristics between Atractylodes japonica and A. macrocephala. Cytogenetic analysis was conducted based on karyotype analysis and physical mapping using fluorescence in situ hybridization. As a result of karyotype analysis by feulgen staining, somatic chromosome numbers of A. japonica and A. macrocephala were 2n=24> The length of the mitotic metaphase chromosomes of A. japonica ranged from 0.70 to 1.60㎛ with a total length of 12.11㎛ and the homologous chromosome complement comprised six metacentrics, five submetacentrics and one subtelocentrics. On the other hand , the length of the mitotic metaphase chromosomes of A. macrocephala ranged from 0.90 to 2.35㎛ with a total length of 16.58㎛ and the homologous chromosome complement comprised seven metacentrics and five submetacentrics. The total length of A. japonica chromosomes was shorter than that of A. macrocephala, but A. japonica had one subtelocentrics (chromosomes 4) different from A. macrocephala chromosomes. The FISH technique using 17S and 5S rDNA was applied to metaphase chromosomes. The signals for 17S rDNA were detected on the telomeric regions of chromosomes 4 and 5 in both A. japonica and A. macrocephala. The 5S rDNA signal was found in the short arm of chromosome 1.