 |
 |
'XX' may be key to women living longer than men WebPosted Wed Mar 29 17:11:01 2000 LONDON - Why do women live longer than men? The answer may lie in their double X chromosomes, according to New Scientist magazine. A woman, unlike a man, has two X chromosomes, one from her father and one from her mother. A woman's body as a result produces slightly different cell lines. And this, researchers say, could give women a biological edge over men. Scandinavian researchers say women's bodies may be able to turn off one of the X chromosomes during the course of their lives to improve their survival. Kaare Christensen of Odense University in Denmark and researchers at Ulleval University Hospital in Oslo studied twins and discovered that the X chromosome was switched off at random in young women. But in women aged 73 to 93, the same cell line was dominant in both twins. According to the magazine, this suggests that one of the cell lines is better than the other. Christensen says males only have one cell line — so they have only one chance. He believes that having the choice of cell lines could help women live longer. According to the magazine, animal studies back the theory. Male mammals have two different sex chromosomes (XY). In general, they have a shorter life span. But it's the opposite in birds. The females have different sex chromosomes (ZW). The males, however, live longer. They have two Z chromosomes. Copyright 2000 CBC All Rights Reserved http://cbc.ca/cgi-bin/templates/view.cgi?/news/2000/03/29/longevity000329 janet paterson 53 now / 41 dx / 37 onset a new voice: http://www.geocities.com/janet313/ 613 256 8340 PO Box 171 Almonte Ontario Canada K0A 1A0