BAR HARBOR, Maine, Oct. 11 (UPI) -- A U.S. study released Monday suggests so-called junk DNA actually may be important for triggering normal development in embryos.
The study found regions of DNA called retrotransposons activate expression of genes in mouse eggs and embryos, researchers at The Jackson Laboratory in Bar Harbor, Maine, write in the October issue of the journal Developmental Cell.
Retrotransposon regions, which appear to have originated from viruses, are found in the DNA of humans, mice and other mammals. They can insert themselves into different spots in the genome and were once thought to be non-functional or junk DNA. Retrotransposons comprise more than one-third of the genome of humans and mice.
In the study, the researchers found certain retrotransposons are very active in mouse eggs and embryos and appear to coordinate the expression of multiple genes critical to development. They also may play an important role in introducing genetic variation and even altering the function of some genes.
In addition, the researchers hypothesize retrotransposons aid in reprogramming the mammalian genome, a process that is necessary for development.
