From: Robina Suwol
Date: 10 Jul 2006
Time: 01:34:43
Remote Name: 70.248.32.137
Thousands of genes behave differently in the same organs of males and females,
researchers reported on Friday, a finding that may help explain why men and
women have different responses to drugs and diseases.
Their study of brain, liver, fat and muscle tissue from mice showed that gene
expression -- the level of activity of a gene -- varied greatly according to
sex.
The same is almost certainly true of humans, the team at the University of
California Los Angeles reported.
"This research holds important implications for understanding disorders such as
diabetes, heart disease and obesity, and identifies targets for the development
of gender-specific therapies," said Jake Lusis, a professor of human genetics
who worked on the study.
Writing in the August issue of Genome Research, the researchers said that even
in the same organ, scores of genes varied in expression levels between the
sexes.
The smallest differences were in brain tissue, they found.
"We saw striking and measurable differences in more than half of the genes'
expression patterns between males and females," said Dr. Thomas Drake, a
professor of pathology. "We didn't expect that. No one has previously
demonstrated this genetic gender gap at such high levels."
Xia Yang, a postdoctoral fellow in cardiology who led the study, said the
implications are important.
"Males and females share the same genetic code, but our findings imply that
gender regulates how quickly the body can convert DNA to proteins," Yang said in
a statement. "This suggests that gender influences how disease develops."
In liver tissue, the findings imply male and female livers function the same,
but at different rates.
"Our findings in the liver may explain why men and women respond differently to
the same drug," Lusis said.
"Studies show that aspirin is more effective at preventing heart attack in men
than women. One gender may metabolize the drug faster, leaving too little of the
medication in the system to produce an effect."
Yang added, "Many of the genes we identified relate to processes that influence
common diseases. This is crucial, because once we understand the gender gap in
these disease mechanisms, we can create new strategies for designing and testing
new sex-specific drugs.