Narrator: This is Science Today. Genes that encode for proteins - "the building blocks of life" - make up about 4% of the genome. For years, the remaining 96% of genes that did not encode for proteins were called "junk" DNA. But in the last five years, scientists have begun to speculate that these genes may not be junk at all.
Lunyak: The original idea was that all this DNA that integrated between the coding portion of the genome - it's actually a leftover and there is not much meaning in that and it probably will disappear in the species when they evolve - but they don't.
Narrator: In fact, Victoria Lunyak, an assistant research scientist at the University of California, San Diego School of Medicine says rather than disappear, there are long stretches of the DNA between coding portions of multiple genomes.
Lunyak: They are in the proper position within the multiple, different genomes and obviously might have some regulatory function or add regulatory flavor to the genome.
Narrator: For Science Today, I'm Larissa Branin.