MicroRNA: A glimpse into the past
The last ancestor we shared with worms, which roamed the seas around 600 million years ago, may already have had a sophisticated brain that released hormones into the blood and was connected to various sensory organs. The evidence comes not from a newly found fossil but from the study of microRNAs - small RNA molecules that regulate gene expression - in animals alive today. Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, have discovered that these molecules are found in the exact same tissues in animals as diverse as sea anemones, worms, and humans, hinting at an early origin of these tissues in animal evolution. Their findings, published today in Nature, also open new avenues for studying the current functions of specific microRNAs...