How Earth's Oddest Mammal Got to Be So Bizarre

Often considered the world's oddest mammal, Australia's beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it has no teeth, lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 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. For instance, their research, which was just published in Nature this month, shows that the platypus lost its teeth roughly 120 million years ago, when four of the eight genes responsible for tooth development disappeared.

A platypus in the wild (Image Credit: Animalia Life)

About the study

1. Advanced gene sequencing technology that combines numerous cutting-edge methods has allowed the research team to map a near-complete genome at the chromosomal level from both the platypus and its cousin, the echidna -- the only two currently living types of monotreme animals. The gene data fills in 90 percent of the gaps in previous genetic mappings. Over 96% of the genome sequences are placed in the chromosomes now.

2. The researchers have compared the monotreme genes and genomes from chickens, humans, rats, Tasmanian devils and lizards.

3. In addition to Yang Zhou (lead author) and Guojie Zhang of the University of Copenhagen, the research was carried out by, among others: Linda Shearwin-Whyatt of The University of Adelaide (Australia) and Jing Li of Zhejiang University (China). A complete list of the authors can be found in the research article.

Below you can find more information for this remarkable study:

https://www.nature.com/articles/s41586-020-03039-0