A New 45S rDNA Locus and Its Genomic Origin in the Amphidiploid of Scilla scilloides Druce

抄録

Two amphidiploids of Scilla scilloides collected in Matsuyama, Japan, had new secondary constrictions at the interstitial region of the long arm of one subtelocentric chromosome in addition to the secondary constriction at the proximal region of the short arms of a pair of subtelocentric b1 chromosomes commonly found in amphidiploids. In situ hybridization using a 45S rDNA probe revealed 3 strong signals at the secondary constrictions and 2 weak signals. Genomic in situ hybridization using 45S rDNA and genomic DNA from either genome A or B indicated that the subtelocentric chromosome with the new 45S rDNA locus was chromosome a₃ of genome A. Genomic Southern analysis showed that the rDNA at the new locus of chromosome a₃ originated from the 45S rDNA of genome B.