Featured Research

from universities, journals, and other organizations

Gene Regulation, Not Just Genes, Is What Sets Humans Apart

Date:
August 13, 2007
Source:
Duke University
Summary:
The striking differences between humans and chimps aren't so much in the genes we have, which are 99 percent the same, but in the way those genes are used, according to new research.

The striking differences between humans and chimps aren't so much in the genes we have, which are 99 percent the same, but in the way those genes are used, according to new research from a Duke University team.

Related Articles


It's rather like the same set of notes being played in very different ways.

In two major traits that set humans apart from chimps and other primates -- those involving brains and diet -- gene regulation, the complex cross-talk that governs when genes are turned on and off, appears to be significantly different.

"Positive selection, the process by which genetic changes that aid survival and reproduction spread throughout a species, has targeted the regulation of many genes known to be involved in the brain and nervous system and in nutrition," said Ralph Haygood, a post-doctoral fellow in the laboratory of Duke biology professor Gregory Wray.

Haygood is lead author in a report on the research to be published online Aug. 12, in the journal Nature Genetics.

His group looked at the regulatory sequences immediately adjacent to 6,280 genes on the DNA of chimps, humans and the rhesus macaque, a more distant primate relative that has 88 percent the same genes as humans. These regulatory stretches of DNA are where proteins bind to the genome to initiate a gene's function. And it is here that evolution has apparently fine-tuned the performance of genes, Wray said, resulting in the dramatic differences in the human brain.

Though many studies have looked for significant differences in the coding regions of genes relating to neural system development and failed to find any, the Duke team believes this is the first study to take a genome-wide look at the evolution of regulatory sequences in different organisms.

Other studies have found significant differences between these species in the coding regions that govern the immune system, the sense of smell and the manufacture of sperm, but the coding regions of neural-related genes had shown very little sign of positive selection in these studies. Yet, as far back as 1975 when Mary-Claire King and Allan Wilson first said humans and chimps were 99 percent the same genetically, they had offered the suggestion that greater differences might be found in the regulatory regions.

The type of analysis performed by the Duke team couldn't be done until the macaque genome was published in 2005 because they needed a third, closely related relative to compare the regulatory sequences.

The mouse genome had been used as a reference point for comparing the coding sequences of humans and chimps, but the non-coding sequences have generally evolved much faster. "Mice wouldn't work for analyzing the non-coding sequences, because they're too different from humans and chimps," Haygood said.

While the biochemistry that cells use to turn food into energy is essentially the same across most animal species, the fine-tuning of how an organism deals with the different sorts of sugars and complex carbohydrates in its diet lies in the regulatory sequences, Wray said.

Chimps are fruit-eaters, for the most part, and would not last long away from their fruit-rich forest. The sugars in their diet are relatively simple to break down and convert to cellular fuel. Humans, on the other hand, eat a wider array of foods, including many the chimps would simply not be able to digest like starchy root crops. The researchers found dramatic differences in the regulatory regions of their genes for breaking down more complex carbohydrates. It may be that parts of the human metabolism are cranked up to digest carbs down to simpler sugars.

"Regulatory changes have adapted to changing circumstances without changing the essential chemistry of metabolism," Wray said. "This may set the stage for a more focused analysis of the human diet."

Much is being written and hypothesized about how dietary changes have contributed to the current human pandemics of obesity and diabetes, and perhaps there will be some insights from understanding how these regulatory sequences have evolved, he said.

To do a genome-wide analysis of regulatory regions, Haygood and post-doctoral fellow Olivier Fedrigo had to adapt some of the statistical tools used for genome-wide analysis of coding regions. To be sure their results would be robust, they focused on just the most reliably accurate published DNA sequences in common between the three animals, discarding two-thirds of the genome to ensure accuracy. "With only three species, we had to be very stringent about quality," Fedrigo said.

The researchers don't think these findings will be of any help resolving questions about how and when the ancestors of humans and chimps diverged on the tree of life, but it's safe to say that "most of this is ancient history," Wray said.


Story Source:

The above story is based on materials provided by Duke University. Note: Materials may be edited for content and length.


Cite This Page:

Duke University. "Gene Regulation, Not Just Genes, Is What Sets Humans Apart." ScienceDaily. ScienceDaily, 13 August 2007. <www.sciencedaily.com/releases/2007/08/070812173244.htm>.
Duke University. (2007, August 13). Gene Regulation, Not Just Genes, Is What Sets Humans Apart. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/08/070812173244.htm
Duke University. "Gene Regulation, Not Just Genes, Is What Sets Humans Apart." ScienceDaily. www.sciencedaily.com/releases/2007/08/070812173244.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Hugging It Out Could Help You Ward Off A Cold

Hugging It Out Could Help You Ward Off A Cold

Newsy (Dec. 21, 2014) Carnegie Mellon researchers found frequent hugs can help people avoid stress-related illnesses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins