| Autor: |
Koehler KE; Department of Genetics, University of California at Davis 95616, USA., Boulton CL, Collins HE, French RL, Herman KC, Lacefield SM, Madden LD, Schuetz CD, Hawley RS |
| Jazyk: |
angličtina |
| Zdroj: |
Nature genetics [Nat Genet] 1996 Dec; Vol. 14 (4), pp. 406-14. |
| DOI: |
10.1038/ng1296-406 |
| Abstrakt: |
Recent studies of human oocytes have demonstrated an enrichment for distal exchanges among meiosis I (MI) nondisjunction events and for proximal exchanges among meiosis II (MII) events. Our characterization of 103 cases of spontaneous X chromosome nondisjunction in Drosophila oocytes strongly parallels these observations. The recombinational histories of MI (97/103) and MII (6/103) nondisjunctional ova were strikingly different. MI nondisjunction occurred primarily in oocytes with non-exchange X chromosomes; of the new nondisjoining exchange bivalents, most carried distal crossovers. Thus, spontaneous MI nondisjunction reflects the failure of the achiasmate segregation systems. MII nondisjunction occurred only in oocytes with proximal exchanges. We propose several models to explain how very proximal exchanges might impair proper segregation. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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