Gene variants accumulate in older males’s sperm; and extra
Old growth: A new study in Nature identifies gene variants that accumulate in sperm as men age and finds that those linked to developmental conditions in children are among the most common. Researchers pinpoint 40 genes—31 of which had not previously been identified—that were under significant positive selection, demonstrating that genes undergoing clonal selection in sperm are more pervasive than previously recognized. “It’s well known that risk for autism in offspring increases with the age of the father and that this is partly attributable to mutations that accumulate in sperm as men age,” wrote Jonathan Sebat, professor of psychiatry and cellular and molecular medicine at the University of California, San Diego, in an email to The Transmitter. In a second Nature study, clonal expansion in human sperm were characterized as “hot spots” of de novo variants. The Transmitter has previously reported that 1 in 15 men carry autism-linked variants in their sperm.
