Researchers in Kobe, Japan, and Montreal, Canada, have uncovered a previously unknown mechanism which causes embryonic germ cells which later develop into sperm or ova to go through a period of "transcriptional silence," during which information from the cell's DNA cannot be copied.
Without this important phase, unique to cells of this type, an organism produces sterile offspring.
The study was conducted by a team led by Dr. Akira Nakamura at the RIKEN Center for Developmental Biology (CDB) in Kobe and by Dr. Paul Lasko, Chair of McGill University's Department of Biology. Their results were published in January, 2008, in the journal Nature.
"A fundamental characteristic of embryonic germ cells in all organisms is that they don't transcribe their own genes for a certain time during embryonic development," Dr. Lasko explained. "They are transcriptionally silent; that's what makes them special. It's not fully understood why this is the case, but if that silencing doesn't happen, then the germ cells don't work. They don't migrate correctly and they don't make their way into the gonads."