Variation in Women's X Chromosomes May Explain Difference Among Individuals, Between Sexes

Variation in Women's X Chromosomes May Explain Difference Among Individuals, Between Sexes

"Variation in Women's X Chromosomes May Explain Difference Among Individuals, Between Sexes
Duke University, March 16, 2005

The first comprehensive survey of gene activity in the X chromosomes of women has revealed an unexpected level of variation among individuals, according to new work by researchers at the Duke University Institute for Genome Sciences & Policy (IGSP) and Pennsylvania State University.

The results may have important implications for understanding the differences in traits among women and between males and females, in terms of both health and disease, said Huntington Willard, Ph.D., director of the IGSP and the study's senior author. The findings also offer new insight into the basis for well-established differences between the sexes, he said.

Willard said that the extensive variation in gene activity in the sex chromosomes means that, in essence, there is not one human genome, but two — male and female.

'We looked at the X chromosomes of 40 women and every one of them had a unique pattern of gene expression,' Willard said. 'All of that variation is completely unique to women. The X chromosomes of males are all the same in this regard.'

Willard and study co-author Laura Carrel, Ph.D., of Penn State, reported their findings in the March 17, 2005, issue of Nature. The National Institutes of Health supported the research. In the same issue of Nature, more than 250 researchers, including Willard and Carrel, reported the complete DNA sequence of the human X chromosome."

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