Consideration of the chromosome evolution on the basis of nuclear DNA content and total chromosome length in lycoris

Abstract

Karyotype analysis and cytophotometrical measurement of DNA content of nucleus were carried out in six species of Lycoris. Consistently with Inariyama (1951 a, b) the present study revealed that L. sprengeri (2n=22) and L. radiata pumila (2n=22) had 22 rod (acrocentric) chromosomes, L. aurea (2n=13) nine V-shaped (metacentric) chromosomes and four rods, L. albiflora (2n=17) five V's and twelve rods, L. squamigera (2n=27) six V's and 21 rods, while L. radiata (2n=33) 33 rods. There found a close proportionality between total chromosome length and relative DNA content of nucleus, and the more the number of V's is, the longer the total chromosome length and the more the DNA content of nucleus. On reference to cytological observations presented by Takemura (1961) and Koyama (1967), it is concluded that the V-shaped chromosome in Lycoris carries the extra segments proper to itself on both sides of the centromere. © 1979, The Genetics Society of Japan. All rights reserved.