Indeed, duck-mouth platypuses are one of the strangest animals on Earth. Known as monotremes as well as the spiny anteater, these two Australian animals similarly lay eggs and feed their young with milk. The genes of these two creatures are very primitive and unchanged.
It is a bizarre mix of vertebrate animals, birds, reptiles, and mammals. Scientists think the platypus genome could reveal secrets about our own evolution. It can also show how our ancestors (mammals) gave birth by lying on eggs from afar. “When the platypus’s entire genome is unraveled, it will provide answers to how the animal’s peculiar features arose.
At the same time, decoding the genomes of platypuses is very important in understanding how other mammals evolved, ”says evolutionary biologist Guojie Zhang of the University of Copenhagen. Although some genome sequences of female platypuses have been deconstructed in previous years, it is not possible to obtain much information without the Y chromosome. Here, the researchers created a high-accuracy genome map using male platypuses.
Mammals today are divided into three groups; monotremes (single-hole), marsupials and mammals (placentals). Humans also belong to the group of placentals. The last two groups fall into a subclass of theria mammals. Theria gives birth to mammals young, but monotremes are simply too different to be included in this group.
Although it is not known how these three different groups are separated from each other, some think that after the monotremes first separated, marsupials and placentals separated. Others think that these three groups diverged from each other at about the same time. Now, thanks to the platypus genome, some dates are beginning to come to light.
The spiny anteater and platypus sequences show that the closest ancestors of these two species lived 57 million years ago. At the same time, monotremes diverged from marsupials and placentals 187 million years ago. Even after all these changes, the semi-aquatic platypus did not change much in the bushes in Australia apart from other marsupials or mammals. Researchers focused specifically on the sex (sex) chromosomes of this animal.
It seems that the platypus evolved independently of other theria mammals, and all chromosomes simply contain the XY pair. However, the platypus is the only animal to contain 10 sex chromosomes. (there are 9 in spiny anteaters). In the platypus, the 5 X, 5 Y chromosomes are organized into a ring, and it seems that during mammalian evolution this was broken into pieces. This sex chromosome information; Compared to humans, opossum, Tasmanian devil, chickens, and lizard genome, the researchers found that the sex chromosomes of the platypus have more in common with chickens, or birds.
She lays eggs but feeds her cubs with milk
Although platypuses lie on their eggs like chickens, they feed their young milk like theria mammals. In fact, this shouldn’t come as a surprise either, monotrem genomes contain milk genes, most of which come from theria mammals. Although casein genes encode most proteins in mammalian milk, it seems that; monotrems contain extra caseins with unknown functions.
So platypus milk is not like cow or human milk. In fact, a study published earlier found that platypus milk can be effective in fighting antibiotic-resistant bacteria. https://www.
Its genome supports this. While birds and reptiles have 3 genes to synthesize essential egg proteins, the platypus seems to have lost these genes 130 million years ago. While chickens today have these 3 egg proteins, humans have none and only one functional copy is left in platypuses.
The platypus is a strange vehicle, its genome as a kind of bridge to our evolutionary past. “We are informed that the milk production seen in all mammalian species was transmitted through the same set of genes derived from the first dinosaurs of the Jurassic period, as well as from a common ancestor that lived more than 170 million years ago,” says Zhang. In addition, when the whole genome was examined, it was revealed that 4 genes related to tooth development probably disappeared 120 million years ago.
Therefore, the platypus grinds what it eats using a pair of horn-like plates. Toxic spurs can possibly be explained by defense genes. In addition, unique proteins allow the poison to biçim. In the entire genome sequence of spiny anteaters (echidna), this venom gene switch appears to have been lost.
The researchers state that these results reveal some similar fascinating biological characteristics of the platypus and spiny anteater. Thanks to these new genome analyzes of the two species, new discoveries of theria mammals and more detailed perspectives on the evolution of egg-laying mammals will be created.
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Explained Why Platypuses Are So Weird
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