EDMONTON – Ever since Europeans discovered the platypus in the late 1700s, the strange, ducky, semi-aquatic creature has lost explorers.
The creature, with its toothless duck-like bill, woven legs, poisonous ankle spikes, and shiny fur, surprised researchers with its seeming loneliness, long before it was discovered that it could both lay eggs. give birth and give milk to his young.
Today’s researchers are still trying to understand the origins of the platypus, which was largely considered the strangest mammal in the world – to date.
For the first time, researchers at the University of Copenhagen have mapped the entire platypus genome, providing answers on how some of the strange features of platypus appeared.
The platypus belongs to an ancient group of mammals – monotremes – that existed millions of years before any modern mammal appeared.
By comparing the genome of the platypus with the sex of one of the other living monotreme species, the echidna with a short beak, researchers can build a better understanding of the genes that led to the specific characteristics of the creatures.
“Of course, the platypus belongs to the class Mammalia. But genetically, it is a mixture of mammals, birds and reptiles. It retained many of the original features of its ancestors – which may contribute to its success in breeding. change to the environment in which they live, “Professor Guojie Zhang, a University of Copenhagen researcher, said in a press release.
Monotremes are famous for their unique ability to lay eggs and nurse young offspring once they are born.
Researchers note that one of the most unusual features of platypus is its ability to feed the young born by expressing milk through sleep. aige.
According to the research, published this week in the journal Nature, due to our own evolution, humans lost their vitellogenin genes, which are important for making egg yolks. Chickens, for example, have these three genes. Instead, we developed casein genes, which are responsible for our ability to produce casein protein, a key component in mammalian milk.
Platypuses still have one vitellogenin gene, despite the loss of the other two about 130 million years ago, which allows them to lay eggs. But they also carry the casein genes, allowing the creatures to develop milk that is very similar to cow’s milk.
“It tells us that milk production in all developed mammal species was developed through the same set of genes derived from a common ancestor who lived more than 170 million years ago, along with the dinosaurs. early Jurassic, ”said Zhang.
ONLY WITH 10 SEX CHROMOSOME
The research has also shed light on one of the most likely platypus topics – determining the nature of the creatures.
All other mammals on earth, including humans, have two sex chromosomes. But the platypus has 10, consisting of five Y chromosomes and five X.
Researchers now believe that the chromosomes were arranged in a ring shape, which was later broken down into many small pieces of X and Y chromosomes in ancient monotreme ancestors.
At the same time, genome mapping reveals that the monotreme sex chromosomes are more similar to chickens than to humans, suggesting an evolutionary link between mammals and birds.
“Coding the genome for platypus is important to advance our understanding of how other mammals evolved, including humans,” explained Zhang from the Department of Biology.
“It’s a key reason why we and other eutherian mammals have become egg-laying animals instead of egg-laying animals.”