Karyotype analysis and physical mapping of rDNAs using bicolor-FISH in Tiarella polyphylla D. don = 헐떡이풀의 핵형분석과 bicolor-FISH를 이용한 물리적 지도 작성

Abstract

Tiarella polyphylla D. Don (Saxifragaceae) is a perennial herb and distributed in China, Japan, Taiwan and Korea. Especially, it only grows in Ulleung island of Korea. It has been using for asthma, bruise and audition troubles with main components of some Triterpenoids and seven oleanolic Saponins. There is only known its chromosomal number rarely and cytogenetic study was not done. From this study, karyotype analysis and chromosomal localization of 5S and 45S rDNAs using bicolor-FISH (fluorescence in situ hybridization) were carried out. The somatic metaphase chromosome number was 2n=2x=14 and the size of chromosomes ranged 1.66∼3.50㎛. The chromosome complement consisted of four pairs of submetacentrics (chromosomes 1, 2, 3 and 6), two pairs of subtelocentrics (chromosomes 5 and 7) and one pair of telocentrics (chromosome 4). We also observed NOR (nucleolus organizer region) on the chromosome 4. In bicolor-FISH, one pair of 55 and 45S rDNA sites was detected on the centromeric region of chromosome 3 and short arm of chromosome 4, respectively. Bicolor FISH was very useful tool for the localization and identification of rDNAs on the chromosomes in Tiarella polyphylla.