PITTSBURGH, Oct. 13 – A team led by a scientist at the
University of Pittsburgh School of Medicine has discovered a
regulatory protein that influences where genetic material gets
swapped between maternal and paternal chromosomes during the
process of creating eggs and sperm. The findings, which shed
light on the roots of chromosomal errors and gene diversity,
appear in tomorrow's issue of Nature. Most cells contain 46
chromosomes, half coming from each parent. But eggs and sperm,
known as germ cells, have half as many so that when they combine
to form an embryo, the correct chromosome number is maintained,
explained senior author Judith Yanowitz, Ph.D., assistant
professor of obstetrics, gynecology and reproductive sciences,
Pitt School of Medicine, a member of the Magee-Womens Research
Institute, and former staff associate at the Carnegie
Institution of Washington, Baltimore. "When germ cells form,
segments of DNA are exchanged, or recombined, between maternal
and paternal chromosomes, leading to greater div