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: How steroid hormones enable plants to grow

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

Researchers discover new strategy germs use to invade cells

7 hours ago

The hospital germ Pseudomonas aeruginosa wraps itself into the membrane of human cells: A team led by Dr. Thorsten Eierhoff and Junior Professor Dr. Winfried Römer from the Institute of Biology II, members of the Cluster ...

Progress in the fight against harmful fungi

7 hours ago

A group of researchers at the Max F. Perutz Laboratories has created one of the three world's largest gene libraries for the Candida glabrata yeast, which is harmful to humans. Molecular analysis of the Candida ...

How steroid hormones enable plants to grow

Aug 19, 2014

Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid ...

Surviving the attack of killer microbes

Aug 19, 2014

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules ...

Histones and the mystery of cell proliferation

Aug 19, 2014

Before cells divide, they create so much genetic material that it must be wound onto spools before the two new cells can split apart. These spools are actually proteins called histones, and they must multiply ...

User comments : 0