To solve the mystery of the ‘little skate,’ a bipedal fish

Although the little skate is a fish, it is known to use its fins as legs to walk, similar to animals that live on earth. The tiny skate is thought to have diverged from the common ancestor of terrestrial tetrapods about 470 million years ago. Previous studies have reported that the neural networks involved in locomotion in skates and small tetrapods are similar, but it has been difficult to study the molecular mechanism of how these networks work. How did the nervous system evolve because there was no high-quality genome. little skates.

In a study published in eLife, a team of researchers constructed a high-quality genome of the little skate using the latest genome scanning technology. The size of the newly sequenced skate genome is 2.13 gigabytes, which is 93% of the predicted genome size, and it is a high quality genome with 17,230 protein genes.

In addition, the research team conducted a comparative analysis with terrestrial animals. A comparative analysis of the transcriptomes of skate and tetrapod motor neurons was performed using the high quality genome of the little skate. Based on these results, genes that are expressed in the same way and genes that are expressed differently were discovered in the nerves.

In a small skate, 10 muscles are involved in moving the fins, while in tetrapods, 50 muscles are involved in moving the limbs. By comparing the two species, the research team proposed a molecular model of how the simple locomotion and complex movements seen in terrestrial tetrapods evolved during evolution. when things.

The research was led by Professor Baek Myung-In of the Department of Brain Sciences, DGIST and was carried out together with research teams from Seoul National University and New York University Medical School. Its importance is that it presented a molecular model of the evolution of the network associated with walking by combining the special abilities of research in the fields of comparative biology, genomics and neurobiology.

Professor Baek Myung-in of the Department of Brain Science said, “There are two types of movement, simple and complex, and this is a fundamental discovery that shows the molecular mechanism of how these types how it arose in the long course of evolution.”