The Y may gain a measure of respect now that researchers have discovered that it is actually a genomic "crystal palace," containing genes that impact male fertility, vast stretches of mirror-image DNA, and an assortment of functional and vestigial genes.
Most significantly, the new studies have unearthed a startling mechanism that the Y chromosome uses to maintain its functionality. It appears that the Y protects its genetic integrity by swapping multiple copies of the same gene within its own structure.
"I have been told for years that the Y chromosome was full of junky repeats, a genetic wasteland," said senior author David Page, a Howard Hughes Medical Institute investigator at MIT's Whitehead Institute for Biomedical Research. "People would ask why we would consider wasting our time mapping and sequencing it. But, in fact, what we see is that it's a crystal palace."
The researchers published their findings in two articles in the June 19, 2003, issue of the journal Nature. Page collaborated with colleagues from the Whitehead Institute, Washington University School of Medicine and the Academic Medical Center in Amsterdam.
According to Page, the team's detailed genomic sequence of the human Y chromosome will contribute to a better understanding of male infertility, as well as certain sex-linked genetic disorders in women. He also speculated that their findings could lead to genomic explanations for differences in disease susceptibility between men and women.
Sex chromosomes in animals and humans include the X chromosome and the much smaller Y chromosome. Females have a pair of X chromosomes and males have both an X and Y chromosome.
Contact: Jim Keeley
Howard Hughes Medical Institute