The genes are among a recently discovered group of genes known as microRNAs, or miRNAs, which were first discovered in worms 12 years ago. Only in the past few years have they become recognized as essential gene regulators in many multicellular organisms, including humans, says senior author Dr. Da-Zhi Wang.

"Our interest is in understanding, at the level of gene expression, how muscle cells develop," said Wang. "As microRNAs are gaining acceptance as global regulators of gene expression, we questioned whether they could be involved in the development of muscle."

The findings are in the latest online edition of the journal Nature Genetics.