Comparing Chimp, Human DNA

Oct 12, 2006

Most of the big differences between human and chimpanzee DNA lie in regions that do not code for genes, according to a new study. Instead, they may contain DNA sequences that control how gene-coding regions are activated and read.

"The differences between chimps and humans are not in our proteins, but in how we use them," said Katherine Pollard, assistant professor at the UC Davis Genome Center and the Department of Statistics.

Pollard and colleagues at UC Santa Cruz led by David Haussler looked for stretches of DNA that were highly conserved between chimpanzees, mice and rats. Then they compared those sequences to the human genome sequence, to find pieces of DNA that had undergone the most rapid change since the ancestors of chimps and humans diverged about five million years ago.

They found 202 "highly accelerated regions" or HARs, which showed a high rate of evolution between humans and chimps. Only three of those regions contain genes that are likely to encode proteins. The most dramatically accelerated region, HAR1, appears to make a piece of RNA that may have a function in brain development.

DNA, deoxyribonucleic acid, carries the genetic instructions for making a chimp, a human, a tulip or an amoeba. RNA (ribonucleic acid) is an intermediate molecule that transcribes those instructions to make proteins.

The other highly accelerated regions do not appear to code for genes at all, but many are located close to genes involved in controlling when other genes get made, or in growth and development.

"They're not in genes, but they're near genes that do some very important stuff," Pollard said.

Typically, noncoding regions of DNA evolve more rapidly than regions carrying genes, as there is no selective pressure to stop mutations from accumulating. But the human-accelerated regions are highly conserved across the other groups of animals the researchers looked at, suggesting that they do have important functions that stop them from varying too much.

The work is published in the journal Public Library of Science (PLoS) Genetics. A separate paper on HAR1 was published Aug. 17 in the journal Nature. The study was funded by the National Institutes of Health and the Howard Hughes Medical Institute.

Source: UC Davis

Explore further: Understanding why animals are healthy offers path to precision medicine

Related Stories

Bacterial genome scalpel can identify key gene regions

Jun 15, 2015

In a study that twists nature's arm to gain clues into the varied functions of the bacterial genome, North Carolina State University researchers utilize a precision scalpel to excise target genomic regions that are expendable. ...

When modern Eurasia was born

Jun 10, 2015

Modern Eurasian peoples are genetically speaking not more than a couple of thousand years old. It was during the Bronze Age that the last major chapters were written in the story of the genetic past of Europe ...

Before we build Jurassic World, we need to study recent extinctions

Jun 09, 2015

It's hard to have a conversation about bringing extinct creatures back to life without a tip-of-the-hat to Jurassic Park, or the latest instalment, Jurassic World, due out Thursday. Massive people-eaters escaping their bonds and ravaging humanity may mak ...

Recommended for you

Genes leave some kids prone to weakness in wrist bones

Jun 29, 2015

Pediatric researchers have discovered gene locations affecting bone strength in wrist bones, the most common site for fractures in children. Children who have those genetic variants may be at higher-than-average risk of wrist ...

Rare gene variant associated with middle ear infections

Jun 29, 2015

Many parents have heard the night-time cry of "my ear hurts." For some children, this might happen frequently beginning in infancy and even persist into adulthood. An international consortium led by those ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.