FISH 에 의한 Aegilops속의 게놈상 rDNA 유전자좌 확인 및 분포

Identification and distribution of rDNA loci on the genomes of Aegilops using FISH(fluorescent in situ hybridization)

FISH (Fluorescent In Situ Hybridization) using pTa71(18S-25S rDNA) and pSc119.2 (repeated sequences from rye) as probes was carried out to locate rDNA loci on the genomes of the 10 diploids, 4 tetraploids and 3 hexaploids in Aegilops. In the diploids of Aegilops, all diploids have one or two major loci of rDNA on the short arms of chromosomes of homoeologous group 1, 5 or 6. The diploids were then classified into 4 different types according to the distribution of major rDNA loci. Ae. speltoides, estimated as a donor species of B genome of T. aestivum was classified into the same group with Ae. mutica and Ae. comosa which have been belonged to Comopyrum Section, indicating different genomic differentiation from the other species in Sitopsis Section. With respect to Aegilops polyploids, the major loci of rDNA were not increased in proportion to each diploid genome during the polyploidization and the minor rDNA loci were detected in all the polyploids. The distribution of rDNA loci implicated that the genomes of polyploids had been established through the structural rearrangements of the chromosomes of donor species.