First genome of marsupial could help better human health

Researchers have announced the publication of the first genome of a marsupial, a part of South American species of opossum. The publication explains how important it is to understand all functional elements in the genome if we are to have the most complete toolbox possible to explore human biology and improve human health.

Washington, May 10 : Researchers have announced the publication of the first genome of a marsupial, a part of South American species of opossum. The publication explains how important it is to understand all functional elements in the genome if we are to have the most complete toolbox possible to explore human biology and improve human health.

The team was led by researchers at the Broad Institute of MIT and Harvard, and supported by the National Institutes of Health (NIH),

"The opossum genome occupies a unique position on the tree of life. This analysis fills a crucial gap in our understanding of how mammalian genomes, including our own, have evolved over millions of years," Nature quoted NHGRI Director Francis S. Collins, M.D., Ph.D, as saying.

"These new findings illustrate how important it is to understand all of the human genome, not just the fraction that contains genes that code for proteins. We must identify all functional elements in the genome if we are to have the most complete toolbox possible to explore human biology and improve human health," he added.

Marsupials are a unique class because they are born at an early stage and attach to their mother's teats. They later complete their growth in a protective pouch.

The opossum genome sequence provides researchers with a fresh focus on the evolutionary origins of the human genome. It explains the variation between placental mammals, such as humans, mice and dogs, and marsupial mammals, such as opossums and kangaroos.

"Marsupials are the closest living relatives of placental mammals. Because of this relationship, the opossum genome offers a unique lens though which to view the evolution of our own genome," said Kirstin Lindblad-Toh, Ph.D., co-director of the Broad Institute's genome sequencing and analysis program and the study's senior author.

Marsupials and the ancestors of placental mammals separated 180 million years ago. By studying the opossum and human genomes, researchers were able to understand genetic features in placental mammals,.

About 95 percent of recent genetic innovation lies in areas of the genome that do not have genes called junk DNA

Researchers now know that junk DNA may have elements that affect the function of genes located closeby, but the full extent of the importance of these non-gene regions is still being revealed. The new results suggest that mammals evolved not so much by inventing new kinds of proteins, as by manipulating the molecular controls that dictate that way and origin of proteins.

Second, many of the new DNA instructions seem to stem from transposons, or "jumping genes," that are in areas considered to be junk DNA.

"Transposons have a restless lifestyle, often shuttling themselves from one chromosome to another," said the study's first author Tarjei Mikkelsen, a Broad Institute researcher.

"It is now clear that in their travels, they are disseminating crucial genetic innovations around the genome," Mikkelsen added.

The study is published in the May 10 issue of Nature.

ANI