Have you ever wondered how related you are to a rat?
An average person would probably respond no to this question, but that same person might also think of their friend as they watch a mouse crawl out of their toilet. Instead of chalking it up to coincidence, scientists have developed a new use for genetic data that can not only explain that friend’s rodent-like snout, but also benefit humanity as a whole.
Comparative Genomics, the latest application of genome sequencing, has become instrumental in understanding evolutionary history and human biology. As its name suggests, this approach involves identifying shared genes of various organisms, specifically genes with conserved functions or molecular structures. With this data, certain organisms can become viable models for studying human diseases, and preexisting knowledge of ancestral lineages can be updated and refined.
Rats, which are widely considered to be close to humans, have been shown to possess genes that parallel those associated with anxiety, heart disease, and multiple sclerosis. These discoveries have made rats a prime subject for genetic mapping of more complex diseases. Meanwhile, the sequence comparison of long-living mammal genomes allowed researchers to identify about 2000 shared genes that facilitate their incredibly long lifespans. Variations in these genes could potentially explain lifespan differences among people.
As for evolution, genome comparisons tend to reveal patterns that conflict with our current understanding of evolution. A shared gene pool found in archaea implies extensive horizontal gene transfer and gene deletion, somewhat undermining the idea that evolution occurred primarily through minute changes passed between generations. Comparisons between the opossum genome and other mammals revealed low similarity in otherwise conserved genes, a consequence of a phenomenon known as “innovation.” These new elements reveal that evolution is more spontaneous than initially thought, reviving discussions on a widely-accepted theory.
Genome comparisons have made the relationships between species more tangible than ever before, and the increasing affordability of this practice means that even more discoveries are sure to come.
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