A molecular cytogenetic analysis of chromosome behavior in Lilium ...

Chapter 5It has not, however, been established that the instability is due to the presence of rDNA siteson both arms of the isochromosome but it does provide an instance of instability in suchnewly produced chromosomes. In Lilium species, there are many 5S and 45S rDNA sites andsome of them are in proximal positions (Lim et al. 2001b). One example is the 45S rDNA siteon the short arm of chromosome 4 of Longiflorum. The isochromosome in the genotype,074051-9 which showed a stable mitosis, might have originated from the short arm ofchromosome 4 of Longiflorum. A critical further investigation of the behaviour of the newlyarisen iso-chromosomes reported in this investigation might shed light on the probable modesof origins of B chromosomes.70