Platypus genome sequenced

08 May 2008

Scientists have revealed for the first time the genetic information, or genome, of the platypus in the journal Nature today.

This enigmatic and unique animal has a fascinating mix of mammal and reptile characteristics and this research reveals the individual gene groups for these traits.

The results give clues to how the different genes may function in other mammals and further help to understand how these genes evolved.

DNA analysis

An international team analysed the DNA from a female platypus and then produced a sequence of the whole genome, the first time this has been done. They compared the genetic information with other mammals and a chicken.

The team identified the genetic areas that correspond to many of the platypus' unusual characteristics.

Unique monotreme

The platypus, Ornithorhynchus anatinus, also known as duck-billed platypus, is a type of mammal called a monotreme - they lay eggs instead of live young. They also produce milk that the youngsters suckle through the mother's abdominal skin as she lacks nipples. The team found that the genes responsible for lactating were preserved since the last common ancestor of monotremes and ancient mammals branched away from each other about 166 million years ago.

Venom producing

Additionally to laying eggs, platypuses share other characteristics with reptiles, such as the production of venom. However, they are the only mammal to deliver their poison using spurs in their hind legs. The team found the corresponding venom genes to be similar to those in reptiles but they had evolved independently of each other in a process known as convergent evolution.

High immunity

The team also found a high number of genes associated with immune responses in the platypus. These may give the youngsters an especially good response to fighting off infections and diseases.

First specimen at Museum

The Natural History Museum looks after the first platypus specimen brought to the UK from Australia more than 200 years ago. It is called the holotype, or type specimen, and is the specimen upon which the description is based. It is often referred to when other similar animals need to be identified.

The Museum has more than 850,000 type specimens and scientists from around the world refer to them whenever a species needs to be researched.

Future

Platypuses live in the waterways of southern and eastern Australia and Tasmania. They are very secretive and rarely breed in captivity so very little is known about their lifestyle and habits. 

Their aquatic habitats face more and more threats from pollution, habitat destruction and climate change, so makes this research and future conservation and understanding of the species all the more important.