Fluorescent banding pattern in chromosomes of Tsuga forrestii and T. sieboldii, Pinaceae

In two East Asian species of Tsuga, T. forrestii and T. sieboldii their somatic chromosomes were investigated by fluorescent banding technique using DNA-base specifically binding fluorochromes of chromomycin A3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI). Their chromosome numbers were commonly 2n=24. Their karyotypes were very similar to each other and consisted of eight pairs of long metacentric chromosomes and four pairs of short chromosomes. The two pairs of the short chromosomes were submetacentric, one pair was metacentric chromosomes, and the shortest chromosome pair was submeta-subtelocentric. After CMA-staining six CMA-bands appeared at interstitial region of each one arm of six long metacentric chromosomes. Positive DAPI-band was not observed and DAPI-negative regions appeared coincident with all CMA-bands. Centromeric regions of DAPI-stained chromosomes were darker than chromosome arms. Karyotypes and their fluorescent banding patterns of the two Tsuga species were very similar to each other. The fluorescent banded karyotypes of the Tsuga species are compared with those of other Pinaceae genera reported.