Mysterious Ultraconserved Segments of DNA
Stanford biologists have recently discovered numerous short strands of ultraconserved DNA in lab mice. Normally, conserving DNA segments through evolution indicates that they encode vital sequences for proper cell operation. But mice missing these segments show no noticeable effects. So what do they do? And how have they managed to have their sequences conserved for so long? So far, no one is sure:
“Interestingly,” said Bejerano, “the longer the sequence has been in us, the less likely it is to be lost. It’s almost like the bricks in the foundation of a building, which hold up the rest of the structure.”
Clearly there remains a lot to be discovered. The upcoming availability of several additional well-sequenced mammalian genomes will give the researchers even more data with which to work. And subjecting the laboratory mice missing the ultraconserved regions to a variety of conditions, such as changes in diet or living conditions, may make more noticeable any differences between them and the mice without changes.
“Evolution is a lot of fun,” said Bejerano, who plans to continue the investigation into what the ultraconserved segments might be doing. “You answer one question, and five others pop up.”
