Biomaterial Database

A "hot spot" of recombination coincides with an interstitial telomeric sequence in the Armenian hamster. 1993

T Ashley, and D C Ward

Department of Genetics, Yale University School of Medicine, New Haven, CT 06510.

The chromosomes of male Armenian hamsters (Cricetulus migratorius) exhibit highly localized terminal and interstitial chiasmata. An interstitial telomeric sequence detected by in situ hybridization was clearly visible at the primary constriction of a large metacentric in both mitotic and meiotic chromosomes. This telomeric sequence was the site of a chiasma in 69% of all 58 diakinesis/metaphase I cells examined. The frequency of meiotic exchange at this site was therefore 34.5%, an extraordinary "hot spot" of recombination. Subsequent chiasma interference can be assumed to reduce recombination and tighten linkage along both arms of male hamster chromosomes. These observations suggest that telomere-promoted recombination may represent a second pathway of recombination, mechanistically different from the more heterodispersed process of meiotic exchange.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008540	Meiosis	A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.	M Phase, Meiotic,Meiotic M Phase,M Phases, Meiotic,Meioses,Meiotic M Phases,Phase, Meiotic M,Phases, Meiotic M
D003412	Cricetulus	A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.	Hamsters, Armenian,Hamsters, Chinese,Hamsters, Grey,Armenian Hamster,Armenian Hamsters,Chinese Hamster,Chinese Hamsters,Grey Hamster,Grey Hamsters,Hamster, Armenian,Hamster, Chinese,Hamster, Grey
D003434	Crossing Over, Genetic	The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.	Crossing Over,Crossing-Over, Genetic,Crossing Overs,Genetic Crossing Over,Genetic Crossing-Over
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012737	Sex Factors	Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.	Factor, Sex,Factors, Sex,Sex Factor
D016615	Telomere	A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.	Telomeres
D017403	In Situ Hybridization	A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.	Hybridization in Situ,Hybridization, In Situ,Hybridizations, In Situ,In Situ Hybridizations