Science & Environment

Newly sequenced DNA - how the kangaroo got its bounce

Tammar wallaby
Tammar wallaby young spend nine months in their mother's pouch

Researchers have laid bare the DNA of a kangaroo species for the first time.

An international team of scientists, writing in the Biomed Central journal, Genome Biology, say they have even indentified a gene responsible for the kangaroo's hop.

The group focussed on a small species of kangaroo that inhabits islands off Australia's south and western coasts.

The tammar wallaby (Macropus eugenii) is only the third marsupial to have its genome sequenced.

Making up the trio are the Tasmanian devil and the South American opossum.

The team says the first kangaroo genome is a milestone in the study of mammalian evolution. The ancestors of kangaroos and other marsupials diverged from other mammals at least 130 million years ago.

Professor Marilyn Renfree of the University of Melbourne, a lead researcher on the project, said: "The tammar wallaby sequencing project has provided us with many possibilities for understanding how marsupials are different from us."

Key marsupial traits

Dr Elizabeth Murchison, a marsupial specialist at the Wellcome Trust Sanger Institute in Cambridge, UK, described the study as "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."

Aside from identifying the "hop" gene, the researchers pinpointed the genes responsible for other key marsupial traits.

For example, tammar wallaby young are only the size of a grain of rice when born. They spend the next stage of their development in their mother's pouch, feeding on her milk.

The pouch is external to the mother's body and therefore the developing animal comes under attack from many pathogens. Antibiotics in the mother's milk are key to the survival of the offspring.

tarram wallaby
This is only the third marsupial genome to be sequenced

Dr Murchison told BBC News: "It's always really valuable to look at an organism that is a bit different to understand how humans and other mammals have evolved.

"It gives you a perspective on mammalian evolution by looking at mammals that have diverged fairly early on, like the kangaroo.

The researchers also studied the way tammar wallaby genes are turned "on" or "off" at different stages of the animal's life cycle and in different parts of the body.

They hope their work may help produce future treatments for human disease.

"This is the first genome project to be led by Australian scientists," commented Dr Murchison.

"It's been a huge project. It's been going on for almost my entire career. I'm from Australia and it was going on when I was an undergraduate there 10 years ago.

"It was a very early conceived genome project and it has evolved through various different stages as genome sequencing technologies have changed a lot. The team has adapted and kept up and so they have a huge amount of data." e.

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