On the origin of telocentric chromosomes in mammals
Authors:
H T Imai
Affiliation:
National Institute of Genetics, Misima, Shizuoka-ken 411, Japan
Abstract:
The origin of mammalian telocentric chromosomes is considered under the classical (fusion) and fission hypotheses using both theoretical analyses of the mechanisms proposed under the two hypotheses, and the published chromosomal data for 723 mammal species. Telocentrics are defined on the basis of short arm size (Sw) as chromosomes with Sw < 0·1(Imai, 1976). The fusion hypothesis lacks adequate models for producing these telocentrics, but their origin is readily understood under the fission hypothesis. Based on these analyses, I propose a cyclical model of chromosome change, symbolized:
