August 21, 2011

Researchers Sequence Kangaroo DNA

While sequencing the DNA of a member of the kangaroo family for the first time, an international team of researchers believe they have identified the gene responsible for the creature's hop, Judith Burns of BBC News reported on Friday.

The project, which is detailed in the latest issue of the journal Genome Biology, centers around the tammar wallaby (Macropus eugenii), a smaller species of kangaroo located on islands off the south and west coasts of Australia.

According to Burns, this marks just the third time a marsupial has had its genome sequenced. She reports that the team behind the feat--which including joint lead authors Marilyn Renfree from the University of Melbourne and Dr Tony Papenfuss from Melbourne´s Walter and Eliza Hall Institute--believes that it is "a milestone in the study of mammalian evolution."

"What is interesting is the surprising similarities as well as the differences in the genes uncovered in this study," Renfree said in an August 19 statement. "The genetic sequence of the tammar wallaby has provided new insights into marsupial early development, lactation and the immune system."

"They give birth to tiny under-developed young after a very short pregnancy, which is then followed by a long and sophisticated lactation period while in the mother´s pouch," she added. "This includes the simultaneous provision of two types of milk from adjacent mammary glands to offspring of different ages. This is like the left breast and right breast making milk of two completely different compositions."

In fact, Burns says that newborn tammar wallaby young are roughly the same size as a grain of rice, and spend much of their early life within the mother's pouch, feeding on her milk.

However, the BBC News reporter adds, the young marsupial is exposed to many pathogens, and antibiotics in that milk is "key to the survival of the offspring" during this phase.

As for the hopping genes, in a University of Melbourne press release, the researchers state that they have discovered "how some genes control the development of the kangaroo´s specialized toes that allow them to hop."

Dr. Elizabeth Murchison, a marsupial specialist at the Wellcome Trust Sanger Institute in Cambridge, told the BBC that the project--which she notes was the first of its kind to be headed up by Australian researchers--was "a wonderful tool for studying the evolution of marsupials, and mammals in general, and an impressive piece of work looking at one of Australia's iconic species."


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