Why mice matter in the field of research

'Mice', one of the most commonly used animals in the field of research. From studying the effects of a vaccine or a drug, to studying the effects of an additional or deleted gene, mice are widely used for research and development. But have you ever wondered why results obtained from studying a particular drug/vaccine in mice are considered to succeed if the drug is used in humans too ? Well, this article is to enlighten on the importance of mice in research.

Common set of genes and associated genetics :

Overall, mice and humans share the same set of genes. Both the mouse and human genomes contain about 3.1 billion base pairs. Only about 5% of the sequence consists of protein-coding regions (genes). Whereas more than 90% of the genome is non-coding DNA, that has no known function and is thus referred to as junk DNA. Owing to the vast amount of non-coding DNA, it is difficult to recognize the genes simply by looking at one sequence alone. Identifying regulatory regions within DNA - the "switches" that turn gene expression on or off, up or down - as they exist only as poorly defined "consensus" sequences is difficult. Talking about the protein-coding regions, the mouse and human genomes are 85% identical, other types of genes are 99% identical while the other are 60% identical. In contrast, the non-coding regions are much less similar (more or less 50%). Therefore, when one compares the same DNA region from human and mouse, the functional elements clearly stand out because of their greater similarity. As per computer softwares developed by scientists, human and mouse sequences alignment of the protein-coding and regulatory regions show them to be similar.

Evolution and its role in similarity of Human and Mice genomes:

As life on earth has developed from many single celled organisms and a set of progressive chemical reactions, humans, mice and other mammals shared a common ancestor approximately 80 million years ago. Thus there is similarity of plenty of genomes of all mammals that are comparably similar.

Why are mice used and not other animals ?:

Now if you ask me that if life evolved from a common ancestor, why mice and not other animals are used as model organisms in research, the answer is that the genes for humans are not only easily found in mouse genome sequence, but also it is possible to test the function of those genes in mice. Thus, results obtained in mice can mimic the effect of DNA alterations that occur in human diseases or the human body. This can help in predicting the consequences of a particular drug/vaccine, etc. on the DNA of humans.

In pic : Monument built by Russian scientists to Honor Lab Rats as a symbol of gratitude for their sacrifices to science. Because without them, many breakthroughs would not have been possible.

- Rachna Jadhav

@theresilientresearcher