In this week's Science, a team of Stanford University-led researchers presents a new theory to explain gene redundancy, suggesting that new genes that duplicate the activity of others persist because they are downregulated to match the expression levels of single-copy genes. The researchers analyzed RNA sequence data for 46 human and 26 mice tissue types and found that subfunctionalization, which has been proposed as an explanation for the retention of duplicate genes, evolves slowly and is rare in mammals. Instead, they discovered that when a duplicate of a gene appears, both copies of the gene reduce their expression quickly, allowing them both to control gene expression normally, supporting the concept of dosage sharing.
And in Science Signaling, a group of Japanese scientists reports mice data implicating a mutation in the intracellular cation channel TRIC-B with collagen defects, which may lead to personalized therapies for a rare disorder. Osteogenesis imperfecta is a hereditary disease characterized by fragile bones and has been linked to collagen defects. Some patients have mutations in TRIC-B, but how these mutations affect their disease is unknown. To answer this question, the researchers deleted the TRIC-B gene in mice, which resulted in animals with brittle skeletons deficient in collagen. Further study showed that osteoblasts in these mice were able to produce collagen, but were unable to secrete it, and experienced impaired calcium handling. Restoring TRIC-B then improved calcium signaling and collagen release.