- Title
- Meiosis in oocytes: predisposition to aneuploidy and its increased incidence with age
- Creator
- Jones, Keith T.
- Relation
- Human Reproduction Update Vol. 14, Issue 2, p. 143-158
- Publisher Link
- http://dx.doi.org/10.1093/humupd/dmm043
- Publisher
- Oxford University Press
- Resource Type
- journal article
- Date
- 2008
- Description
- Mammalian oocytes begin meiosis in the fetal ovary, but only complete it when fertilized in the adult reproductive tract. This review examines the cell biology of this protracted process: from entry of primordial germ cells into meiosis to conception. The defining feature of meiosis is two consecutive cell divisions (meiosis I and II) and two cell cycle arrests: at the germinal vesicle (GV), dictyate stage of prophase I and at metaphase II. These arrests are spanned by three key events, the focus of this review: (i) passage from mitosis to GV arrest during fetal life, regulated by retinoic acid; (ii) passage through meiosis I and (iii) completion of meiosis II following fertilization, both meiotic divisions being regulated by cyclin-dependent kinase (CDK1) activity. Meiosis I in human oocytes is associated with an age-related high rate of chromosomal mis-segregation, such as trisomy 21 (Down’s syndrome), resulting in aneuploid conceptuses. Although aneuploidy is likely to be multifactorial, oocytes from older women may be predisposed to be becoming aneuploid as a consequence of an age-long decline in the cohesive ties holding chromosomes together. Such loss goes undetected by the oocyte during meiosis I either because its ability to respond and block division also deteriorates with age, or as a consequence of being inherently unable to respond to the types of segregation defects induced by cohesion loss.
- Subject
- aneuploidy; meiosis; cocyte; fertilization
- Identifier
- uon:6538
- Identifier
- http://hdl.handle.net/1959.13/804156
- Identifier
- ISSN:1355-4786
- Language
- eng
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