Featured Research

from universities, journals, and other organizations

Rice Genome Approaches Completion

Date:
February 5, 2005
Source:
Public Library Of Science
Summary:
A large group of scientists led by the Beijing Institute of Genomics is publishing a much improved, near-complete genome analysis of the indica and japonica subspecies of O. sativa, which are eaten in India and China, and Japan, respectively. Their analysis team, led by Gane Ka-Shu Wong, provides important insights into the evolution of rice.

Rice (Oryza sativa).
Credit: Photo courtesy of Max Planck Society

In April 2002, Science published draft genome sequences for the two major subspecies of cultivated rice, Oryza sativa. The release of the rice genome—the first plant crop to be sequenced—was big news. Rice is a staple crop for more than half of the world’s population, and it was hoped that the availability of the genome sequence might enable scientists to develop more productive rice strains or strains that are more environmentally friendly. Furthermore, the rice genome might provide the key to understanding the genetics of other major cereal crops, all of which have much larger genomes.

But the sequences published in 2002 were only draft genomes, containing many gaps and errors—works-in-progress rather than finished products. Now, a large group of scientists led by the Beijing Institute of Genomics is publishing a much improved, near-complete genome analysis of the indica and japonica subspecies of O. sativa, which are eaten in India and China, and Japan, respectively. Their analysis team, led by Gane Ka-Shu Wong, provides important insights into the evolution of rice.

First of all, the team improved their original whole-genome shotgun sequencing of indica by generating significantly more sequence data, and then they used better methods to assemble these data. In whole-genome shotgun sequencing, the entire genome is chopped into random fragments, each fragment is sequenced, and then powerful computer programs search for overlaps and put all these data in order. It’s like putting a fiendishly difficult jigsaw puzzle together by looking for patches of matching color.

The key to the improvement in the genome sequence analysis is that the researchers have used the combined DNA sequence data from the two subspecies to facilitate the sequence assembly. The result is a nearly 1,000-fold increase in contiguity for the two genome sequences. In other words, while the original draft was very fragmented, in the new version, 97.7% of the genes can be found, in either the indica or the japonica dataset, on one piece of DNA whose position along the chromosomes is well defined.

The researchers have also used their improved genome sequence to investigate the evolutionary history of rice. Central to evolution is the development of new functions through mutation of existing genes. But when mutations occur in functional genes, the result is rarely beneficial, so it is thought that evolution is more likely to proceed first by duplicating existing genes and then experimenting on the “backup” copy of the gene. Wong and colleagues report that there is evidence in the rice DNA sequences for a whole-genome duplication event just before the grasses diverged from other flowering plants, about 55–70 million years ago. This genome duplication may have played a role in the origin of the grasses, which then spread rapidly across the world to provide important sources of food that, among other things, possibly influenced human evolution.

Analysis of the rice genomes also indicates that a small chromosomal segment was duplicated about 21 million years ago and that there is massive ongoing duplication of individual genes. These individual gene duplications provide a continuous source of raw material for gene genesis and very likely contribute to the differences between members of the grass family. Now the challenge is to use the rice sequences as a basis for detailed genetic analyses of additional cereal crops and for the development of improved strains of not only rice, but wheat, maize, and other important food crops.


Story Source:

The above story is based on materials provided by Public Library Of Science. Note: Materials may be edited for content and length.


Cite This Page:

Public Library Of Science. "Rice Genome Approaches Completion." ScienceDaily. ScienceDaily, 5 February 2005. <www.sciencedaily.com/releases/2005/02/050201110911.htm>.
Public Library Of Science. (2005, February 5). Rice Genome Approaches Completion. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2005/02/050201110911.htm
Public Library Of Science. "Rice Genome Approaches Completion." ScienceDaily. www.sciencedaily.com/releases/2005/02/050201110911.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
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


Plants & Animals

Earth & Climate

Fossils & Ruins

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