Evolution: It’s all in how you splice it
When genes were first discovered, the canonical view was that each gene encodes a unique protein. However, biologists later found that segments of genes can be combined in different ways, giving rise to many different proteins.This phenomenon, known as alternative RNA splicing, often alters the outputs of signaling networks in different tissues and may contribute disproportionately to differences between species, according to a new study from MIT biologists.After analyzing vast amounts of genetic data, the researchers found that the same genes are expressed in the same tissue types, such as liver or heart, across mammalian species. However, alternative splicing patterns — which determine the segments of those genes included or excluded — vary from species to species. “The core things that make a heart a heart are mostly determined by a heart-specific gene expression signature. But the core things that make a mouse a mouse may disproportionately derive from splicing...