Skip to Content

Finding Evolution’s Signatures

Comparing genomes of different animals allows scientists to decipher hidden elements in the human genome.
September 1, 2006

Though researchers have finished sequencing the human genome, it is still far from understood. A major objective of biotechnology is to develop the experimental and computational tools necessary for deciphering the signals encoded within the genome and to understand their role in human health and disease.

Illustration by Harry Campbell

Much remains unknown. It is still a matter of debate exactly how many genes the genome encodes, or even how a gene should be defined. In addition, scientists are just beginning to understand the array of regulatory sequences that punctuate the genome and dictate when certain genes are turned on and off. The complex code within these elements has yet to be deciphered.

Comparative genomics can shed the powerful light of evolution on these unknowns. Functional regions of the DNA sequence, such as genes and regulatory regions, have been well conserved, remaining largely unchanged across related species through millions of years of evolution; but DNA sequences that do not code for genes or regulatory regions change more rapidly. To help us understand the evolutionary constraints of functional elements in the human genome, the National Human Genome Research Institute has recently expanded its sequencing efforts to include additional mammalian genomes.

In my group, instead of simply searching for highly conserved elements, we search for elements that have changed in particular ways. By comparing various genomes, we have found several evolutionary signatures–common patterns in the way a particular DNA sequence has evolved over time. We are now using these evolutionary signatures to reanalyze the human, yeast, and fly genomes and have already uncovered hundreds of novel genes, novel exons, and unusual gene structures.

We have also used genome-wide conservation patterns to define subtle regulatory motifs that are another type of evolutionary signature. Coupled with rapid string search algorithms, these signatures have led to the discovery of a complete dictionary of known and novel regulatory elements in the human, yeast, and fly, revealing the building blocks of gene regulation.

These evolutionary signatures are universal across kingdoms of life. With complete genomes, we can use them to elucidate common evolutionary principles, interpret our genome, study human variation and evolution, and revolutionize our understanding of human biology.

Manolis Kellis, one of the TR35, is an assistant professor of computer science at MIT.

Keep Reading

Most Popular

Workers disinfect the street outside Shijiazhuang Railway Station
Workers disinfect the street outside Shijiazhuang Railway Station

Why China is still obsessed with disinfecting everything

Most public health bodies dealing with covid have long since moved on from the idea of surface transmission. China’s didn’t—and that helps it control the narrative about the disease’s origins and danger.

individual aging affects covid outcomes concept
individual aging affects covid outcomes concept

Anti-aging drugs are being tested as a way to treat covid

Drugs that rejuvenate our immune systems and make us biologically younger could help protect us from the disease’s worst effects.

Europe's AI Act concept
Europe's AI Act concept

A quick guide to the most important AI law you’ve never heard of

The European Union is planning new legislation aimed at curbing the worst harms associated with artificial intelligence.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.