FISH and GISH analysis of Brassica genomes

摘要

Fluorescence and genomic in situ hybridization (FISH and GISH) methods were used for discrimination of Brassica genomes. The three diploid and three allotetraploid species of Brassica, known as the "U-triangle," represent an attractive model for molecular and cytological analysis of genome changes during phylogeny in the genus Brassica. The use of genomic DNA probes enabled unambiguous discrimination of the ancestral genomes in B. juncea and B. carinata, and was only partially successful in B. napus. GISH signals in all genomes were localized predominantly in pericentromeric regions of chromosomes. Simultaneous application of genomic and ribosomal DNA probes in multicolor GISH and FISH allowed identification of a significant number of chromosomes in the B.juncea complement. The study also revealed that species of Brassica possess Arabidopsis-type telomeric repeats which in all genomes occupied exclusively terminal, that is, telomeric, locations of chromosomes.