Tuesday, 24 July 2007

Most egg cells in a female body die naturally

Most egg cells in a female body die naturally by programmed cell death July 24, 2007 Some facts: A 20-week-old human female foetus has around 7 million potential egg cells, or oocytes, in her developing ovaries. By birth this number has dropped to 1 million, and by puberty it is only some 300,000 cells left. Programmed cell death - apoptosis - takes the oocytes out. 'Death by neglect' is one possible explanation for this regulated drop in numbers. 'Death by defect' is another possibility. Distinct ‘killer molecules’ is involved in this form of apoptosis. The body puts in a quality control check, which cannot be overridden, to screen out bad eggs. For example, oocytes that are stalled during cell division will in this way be removed. Furthermore, in each menstrual cycle around 15 oocytes start to mature. Usually only one of these is chosen for release and possible fertilisation and the rest die off. The healthiest egg – ‘the one that gets ahead of the pack’ - may out-compete the rest to ensure the best end result – a healthy offspring. When a woman's supply of oocytes runs out she will enter the menopause. During the entire lifespan, only a few egg cells will become a healthy baby (0 to at the most 15 or 20 still in some cultures). The question:

What is so special with egg cells, so that they can’t be used for research or cure? Most, sometimes all will die anyway!

See also: Human Ovulation Caught on Camera CellNEWS - Wednesday, 18 June 2008 Most egg cells in a female body die naturally by programmed cell death CellNEWS - Tuesday, 24 July 2007 How much is a human egg worth? CellNEWS - Wednesday, 21 February 2007 Back to the question: How much is a human egg worth? CellNEWS - Tuesday, 09 October 2007 ........ ZenMaster


For more on stem cells and cloning, go to CellNEWS at http://www.geocities.com/giantfideli/index.html

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