Specialization in the behaviour of chromosomes on the meiotic spindle
β Scribed by J. Sybenga
- Publisher
- Springer Netherlands
- Year
- 1981
- Tongue
- English
- Weight
- 991 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0016-6707
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β¦ Synopsis
The kinetic activity of chromosomes is either distributed evenly along the length of the chromosome or localized in a single centromere. Within the group of organisms with evenly distributed (holokinetic) activity great variation occurs, which has its consequences for chromatid segregation. Three major types, with some overlap, can be distinguished. They form a gradient of increasing specialization. Arguments are presented for the hypothesis that the monokinetic chromosomes are nothing but the end point in the same gradient and do not form a fundamentally different category. These arguments include: concentration of kinetic activity at meiosis in some types of holokinetic chromosomes, and 'atavistic' traits in monokinetic chromosomes pointing to a holokinetic origin. Possible reasons for the wide distribution of monokinetic chromosomes in the more evolved taxa are given.
π SIMILAR VOLUMES
A single population of Briza humilis contained two types of B chromosome, one a large ( BL) and the other a small (Bs) acrocentric. DNA measurements show that the BL chromosome contains approximately twice as much DNA per unit length as the members of the regular complement. The meiotic pairing beha