Mice, Humans Carry Similar Genes But Express Them Differently

Many science experiments are often used on mice before they're tried in clinical trials with humans. An ethical perspective is oftentimes considered for initial testing periods, but researchers also conduct certain medical possibilities with mice because these animals share more of their genes with humans.

Now, recent findings published in the Proceedings of the National Academy of Sciences (PNAS) show that with similarities, many of the genes are expressed differently in humans versus mice. In fact, researchers analyzed 15 different genes that were expressed in both humans and mice.They discovered that gene expression clustered around these species more so than tissue type. 

"Although commonalities are evident in the expression of tissue-specific genes between the two species, the expression for many sets of genes was found to be more similar in different tissues within the same species than between species," said co-senior authors Joseph Ecker, at the Salk Institute for Biological Studies, Stanford University's Michael Snyder, and their colleagues, via Genome Web.

For the study, researchers discovered over 4,000 genes that were expressed differently by the two species--suggesting that the results could not likely be attributed to an artifact or experimental process. Those included 2,569 genes with enhanced expression in human tissues and almost 2,200 genes with more pronounced expression in tissues from mouse.

As scientists have believed that animals that are similar to use in many ways probably also experience gene expression in similar ways as well, this may not always be the case. For instance, gene expression in different types of mice tissue was found to be more alike than same tissue types in humans. Yet heart tissue in mice was also found to be similar to liver tissue and heart tissue found in humans.

"Overall, our study demonstrates the extensive divergence in the expression of both non-coding genes as well as conserved, protein-coding genes that likely mediates the extensive differences between humans and mice," the study's authors concluded.