Good news and bad for dad this Father's Day

New study explores dad's role in shaping a healthy baby

SALT LAKE CITY, June 14, 2009 -- It was long believed that conception does not involve a meeting of equals. The egg is a relatively large, impressive biological factory compared with the tiny sperm, which delivers to the egg one copy of the father's genes. However, a new study from Huntsman Cancer Institute (HCI) at the University of Utah reveals that the father's sperm delivers much more complex genetic material than previously thought. The findings could lead to a diagnostic test to help couples deal with infertility.

Researchers discovered particular genes packaged in a special way within the sperm, and that may promote the development of the fetus.

"Our findings show that the father plays an active role in packaging his genome to help ensure a healthy baby," says study co-leader Brad Cairns, Ph.D., investigator with HCI and the Howard Hughes Medical Institute, and professor of oncological sciences at the University of Utah. "However, they also raise the possibility that a man's aging, health and lifestyle may alter this packaging and negatively affect fertility and embryo development."

During fetal development, certain genes make decisions about organ and tissue development. The new research shows that in sperm, these genes are wrapped in special packaging materials called 'modified histones.' These modified histones appear to be key factors in ensuring genes are activated or repressed at the right level, place and time, which helps the fertilized egg develop properly.

Chromosomes are long strands of DNA containing thousands of genes, and their packaging helps determine which genes turn on and off. Understanding how these genes are activated or repressed leads to a better understanding of how disorders like birth defects and cancer develop.