Featured Research

from universities, journals, and other organizations

Reading history through genetics

Date:
December 5, 2012
Source:
Columbia University
Summary:
An engineering study demonstrates a new approach used to analyze genetic data to learn more about the history of populations. The authors, the first to develop a method that can describe in detail events in recent history, focused on two populations, the Ashkenazi Jews and the Masai people of Kenya.

Computer scientists at Columbia's School of Engineering and Applied Science have published a study in the November 2012 issue of The American Journal of Human Genetics (AJHG) that demonstrates a new approach used to analyze genetic data to learn more about the history of populations. The authors are the first to develop a method that can describe in detail events in recent history, over the past 2,000 years. They demonstrate this method in two populations, the Ashkenazi Jews and the Masai people of Kenya, who represent two kinds of histories and relationships with neighboring populations: one that remained isolated from surrounding groups, and one that grew from frequent cross-migration across nearby villages.

"Through this work, we've been able to recover very recent and refined demographic history, within the last few centuries, in contrast to previous methods that could only paint broad brushstrokes of the much deeper past, many thousands of years ago," says Computer Science Associate Professor Itsik Pe'er, who led the research. "This means that we can now use genetics as an objective source of information regarding history, as opposed to subjective written texts."

Pe'er's group uses computational genetics to develop methods to analyze DNA sequence variants. Understanding the history of a population, knowing which populations had a shared origin and when, which groups have been isolated for a long time, or resulted from admixture of multiple original groups, and being able to fully characterize their genetics is, he explains, "essential in paving the way for personalized medicine."

For this study, the team developed the mathematical framework and software tools to describe and analyze the histories of the two populations and discovered that, for instance, Ashkenazi Jews are descendants of a small number -- in the hundreds -- of individuals from the late medieval times, and since then have remained genetically isolated while their population has expanded rapidly to several millions today.

"Knowing that the Ashkenazi population has expanded so recently from a very small number has practical implications," notes Pe'er. "If we can obtain data on only a few hundreds of individuals from this population, a perfectly feasible task in today's technology, we will have effectively collected the genomes of millions of current Ashkenazim." He and his team are now doing just that, and have already begun to analyze a first group of about 150 Ashkenazi genomes.

The genetic data of the Masai, a semi-nomadic people, indicates the village-by-village structure of their population. Unlike the isolated Ashkenazi group, the Masai live in small villages but regularly interact and intermarry across village boundaries. The ancestors of each village therefore typically come from many different places, and a single village hosts an effective gene pool that is much larger than the village itself.

Previous work in population genetics was focused on mutations that occurred very long ago, say the researchers, and therefore able to only describe population changes that occurred at that timescale, typically before the agricultural revolution. Pe'er's research has changed that, enabling scientists to learn more about recent changes in populations and start to figure out, for instance, how to pinpoint severe mutations in personal genomes of specific individuals -- mutations that are more likely to be associated with disease.

"This is a thrilling time to be working in computational genetics," adds Pe'er, citing the speed in which data acquisition has been accelerating; much faster than the ability of computing hardware to process such data. "While the deluge of big data has forced us to develop better algorithms to analyze them, it has also rewarded us with unprecedented levels of understanding."


Story Source:

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


Journal Reference:

  1. Pier Francesco Palamara, Todd Lencz, Ariel Darvasi, Itsik Pe’er. Length Distributions of Identity by Descent Reveal Fine-Scale Demographic History. The American Journal of Human Genetics, 2012; 91 (5): 809 DOI: 10.1016/j.ajhg.2012.08.030

Cite This Page:

Columbia University. "Reading history through genetics." ScienceDaily. ScienceDaily, 5 December 2012. <www.sciencedaily.com/releases/2012/12/121205113528.htm>.
Columbia University. (2012, December 5). Reading history through genetics. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2012/12/121205113528.htm
Columbia University. "Reading history through genetics." ScienceDaily. www.sciencedaily.com/releases/2012/12/121205113528.htm (accessed September 18, 2014).

Share This



More Fossils & Ruins News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Egypt Denies Claims Oldest Pyramid Damaged in Restoration

Egypt Denies Claims Oldest Pyramid Damaged in Restoration

AFP (Sep. 17, 2014) Egypt's antiquities minister denied Tuesday claims that the Djoser pyramid, the country's first, had been damaged during restoration work by a company accused of being unqualified to do such work. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
King Richard III's Painful Cause Of Death Revealed

King Richard III's Painful Cause Of Death Revealed

Newsy (Sep. 17, 2014) King Richard III died in the Battle of Bosworth in 1485, and now researchers examining his skull think they know how. Video provided by Newsy
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Museum Traces Fragments of Star-Spangled Banner

Museum Traces Fragments of Star-Spangled Banner

AP (Sep. 12, 2014) As the Star-Spangled Banner celebrates its bicentennial, Smithsonian curators are still uncovering fragments of the original flag that inspired Francis Scott Key's poem. (Sept. 12) Video provided by AP
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:
from the past week

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