In all other mammals, vitellogenin genes have been replaced with casein genes, which are responsible for our ability to produce casein protein, a major component in mammalian milk. This is probably because it is not as dependent on creating yolk proteins as birds and reptiles are, as platypuses produce milk for their young. The platypus continues to lay eggs by virtue of this one remaining gene. The study demonstrates that platypuses still carry one of these three vitellogenin genes, despite having lost the other two roughly 130 million years ago. Chickens on the other hand, continue to have all three. One of the platypus' most unusual characteristics is that, while it lays eggs, it also has mammary glands used to feed its babies, not through nipples, but by milk - which is sweat from its body.ĭuring our own evolution, we humans lost all three so-called vitellogenin genes, each of which is important for the production of egg yolks. It has preserved many of its ancestors’ original features - which probably contribute to its success in adapting to the environment they live in,' says Professor Zhang. But genetically, it is a mixture of mammals, birds and reptiles. 'Indeed, the platypus belongs to the Mammalia class. The platypus belongs to an ancient group of mammals - monotremes - which existed millions of years prior to the emergence of any modern-day mammal.

It holds the key as to why we and other eutheria mammals evolved to become animals that give birth to live young instead of egg-laying animals,' explains Professor Guojie Zhang of the Department of Biology. At the same time, decoding the genome for platypus is important for improving our understanding of how other mammals evolved - including us humans. 'The complete genome has provided us with the answers to how a few of the platypus’ bizarre features emerged. The study has been published in the scientific journal, Nature. For the first time, an international team of researchers, led by University of Copenhagen biologists, has mapped a complete platypus genome. Their understandings have now advanced, to a great degree. Modern day researchers are still trying to understand how the platypus - often considered to be the world's oddest mammal - got to be so unique. Ever since Europeans discovered the platypus in Australia during the late 1700’s, the quirky, duck-billed, semiaquatic creature has baffled scientific researchers. It lays eggs, but nurses, it is toothless, has a venomous spur, has webbed feet, fur that glows and has 10 sex chromosomes. Now, an international team of researchers led by University of Copenhagen has conducted a unique mapping of the platypus genome and found answers regarding the origins of a few of its stranger features. Often considered the world's oddest mammal, Australia’s beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 10 sex chromosomes.

Duck billed platypus facts