Hello,

We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not a subscriber? Subscribe now for unlimited access to online articles.

Rewriting Life

Finding Evolution's Signatures

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

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.

This story is part of our September/October 2006 Issue
See the rest of the issue
Subscribe

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.

Tech Obsessive?
Become an Insider to get the story behind the story — and before anyone else.

Subscribe today
More from Rewriting Life

Reprogramming our bodies to make us healthier.

Want more award-winning journalism? Subscribe to Print + All Access Digital.
  • Print + All Access Digital {! insider.prices.print_digital !}*

    {! insider.display.menuOptionsLabel !}

    The best of MIT Technology Review in print and online, plus unlimited access to our online archive, an ad-free web experience, discounts to MIT Technology Review events, and The Download delivered to your email in-box each weekday.

    See details+

    12-month subscription

    Unlimited access to all our daily online news and feature stories

    6 bi-monthly issues of print + digital magazine

    10% discount to MIT Technology Review events

    Access to entire PDF magazine archive dating back to 1899

    Ad-free website experience

    The Download: newsletter delivery each weekday to your inbox

    The MIT Technology Review App

/3
You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.