Genomic 'haircut' makes world's tiniest genome even smaller: research

Sep 21, 2010

The world's tiniest nuclear genome appears to have "snipped off the ends" of its chromosomes and evolved into a lean, mean, genome machine that infects human cells, according to research published today by University of British Columbia scientists.

Until recently, E. cuniculi, a commonly found in rabbits that can also be fatal to immunocompromised humans, has been widely regarded as having the smallest known nuclear . At 2.9 millions base pairs (Mbp) and approximately 2,000 genes, the genome of E. cuniculi is less than one-two thousandth the size of the human genome.

But now, a team of researchers led by UBC Botany Prof. Patrick Keeling sequenced the genome of a closely related parasite that makes the E. cuniculi genome seem positively king-sized. The genome of E. intestinalis, a sister species of E. cuniculi that infects human intestines, is 20 per cent smaller, at only 2.3Mbp.

"On one end of the spectrum, genomes can get larger almost without limit, but there is a limit to how small they can get - they can't be less than zero," says Keeling, whose work is published in today's issue of the journal Nature Communications. "And the question that fascinated us was 'in an already tiny genome, what else can be lost'?"

Keeling and a team of researchers from Switzerland, Canada and the U.S. compared the genome of E. cuniculi and E. intestinalis and found little difference between the chromosome "cores" but that the ends were all "trimmed" in E. intestinalis.

"The are long threads of DNA, and in E. intestinalis its almost as though it got a haircut, removing hundreds of genes, but all from the ends of the threads," says Keeling.

Keeling, director of the Centre for and Evolution and a member of Beaty Biodiversity Research Centre at UBC, says the discovery provides insights into how genomes evolve, especially in .

Explore further: Mycologist promotes agarikon as a possibility to counter growing antibiotic resistance

Related Stories

Mouse to man: The story of chromosomes

Apr 19, 2006

U.S. scientists say sequencing human chromosome 17 and mouse chromosome 11 has offered unique insights into the evolution of the genome of higher mammals.

New genome sequencing targets announced

Jul 24, 2006

The U.S. National Human Genome Research Institute has announced several new sequencing targets, including the northern white-cheeked gibbon.

Human chromosome 3 is sequenced

Apr 27, 2006

The sequencing of human chromosome 3 at Baylor College represents the final stage of a multi-year project to sequence the human genome.

Horse genome sequence draft is issued

Feb 07, 2007

The U.S.-led Horse Genome Sequencing Project has issued its first draft, making it available to biomedical and veterinary scientists around the world.

Recommended for you

YEATS protein potential therapeutic target for cancer

Oct 23, 2014

Federal Express and UPS are no match for the human body when it comes to distribution. There exists in cancer biology an impressive packaging and delivery system that influences whether your body will develop cancer or not.

Precise and programmable biological circuits

Oct 23, 2014

A team led by ETH professor Yaakov Benenson has developed several new components for biological circuits. These components are key building blocks for constructing precisely functioning and programmable bio-computers.

User comments : 0