Analysis of Karyotypes of Scilla permixta and the Allied Species with Special Reference to the Dislocation of the Chromosome

Abstract

The karyotypes of Scilla peruviana, S. peruviana var. alba, S. permixta and S. ughii were analysed from the point of view of karyotype alteration. The former two have a similar karyotype, namely, 2n=16=2L+8M+6S. S. permixta has three kinds of karyotype, namely, 2n=16=2L+8M+6S, 2n=15=2L+8M+5S and 2n=14=2L+8M+4S. The first type has two satellited S₃ chromosomes, the second only one S₃ and the last has no satellited S₃ chromosomes, but one of the medium M₃ chromosome has a translocated S₃ chromosome which has no satellite at the idstal end. This observation suggests that SAT-chromosomes are the result of such a translocation of other chromosomes as in S. permixta.
It is also suggested that the secondary constrictions may indicate the process of cutting in chromosomes or the trace of simple or reciprocal translocations of chromosomes.
S. ughii has various karyotypes, i.e., 2n=17=2L+8M+7S, 2n=19 =2L+9M+8S, 2n=20=3L+11M+6S, 2n=22=3L+11M+8S and seems to be of hybrid or triploid origin.
The karyotype alterations such as fragmentation (cf. SATO 1935), elimination, translocation and hybridization after these alterations of chromosomes in Scilla support NAVASHIN'S dislocation hypothesis of evolution of chromosomes (cf. NAVASHIN 1932).