According to new atlas, a foreign media report, genome sequencing can let scientists know a lot of information about a species,Now scientists have sequenced the genome of the Australian lungfish, one of the strangest and most interesting animals in the world.Australian lungfish is considered as a "living fossil". Its genome shows that it has the largest genome of all animals sequenced so far.
Combined with these two characteristics, Australian lungfish like to climb out of their homes in rivers and freshwater pools and venture to dry land. It's not really an amphibian, but it's known to live out of water for a few days - as long as its skin isn't too dry.
This is one of the most important steps in evolutionary history. In the Devonian period, about 420 million years ago, when the first animals crawled from the ocean to dry land, the Australian lungfish was one of the closest relatives of these pioneer marine organisms, and its genome may have preserved the understanding of that critical period because it had little change in the evolution process of more than 100 million years.
The results showed that the genome of Australian lungfish was the largest ever sequenced, containing about 43 billion DNA base pairs. This is 14 times more than the human genome, much more than the 32 billion DNA base pairs of the previous record holder, the blunt mouth newt.
The team found that the astonishing scale was largely due to repetition. About 90% of the genome of lung fish is composed of repetitive sequences, and the position of these sequences in the genome will change. In this regard, the team says that lungfish are actually closer to terrestrial vertebrates than other fish. With the complete sequencing of the genome, researchers can confirm that lungfish are the closest living relatives of tetrapods, and tetrapods are an absolutely huge group of terrestrial animals, including amphibians, reptiles, birds, mammals, etc.
Scientists have found that the genes that control the development of lung embryos in lungfish are the same as those in humans, indicating that the evolution of the two species can be traced back to the same origin. Their fin bone development is also controlled by the same genes as our hands. The team also found some genomic adaptations to terrestrial life. The genome of lungfish has expanded in areas related to air breathing, limb development, reproduction and olfactory ability. All in all, sequencing the genome of the Australian lungfish will help improve our understanding of one of the most important transitions in evolutionary history.
The study was published inNatureIn the magazine.