Zebrafish tests identify a gene potentially at the root of domestication

Researchers at Queen Mary University of London have shown that zebrafish can provide genetic clues to the evolution of social behaviors in humans and domesticated species.

The investigatepublished in iSciencelooked genetically modified zebra fish that fail to produce the baz1b protein. The results suggest that the gene is not just the cornerstone of physical and behavioral changes in fish and other domesticated animals. speciesbut potentially also the social relationships of human beings.

Domesticated species, such as dogs and cats, show genetic differences compared to their wild-type counterparts, including the variation in the baz1b gene. These genetic changes correlate with physical and behavioral traits, including smaller facial features like skulls and teeth, as well as being more sociopositive, less aggressive, and less fearful.

However, studies have also suggested that modern humans they were domesticated after diverging from their extinct relatives, the Neanderthals and Denisovans. In doing so, we experience similar physical and behavioral changes.

All of these changes have been linked to the fact that domestic animals have fewer of a certain type of stem cells, called neural crest stem cells.

Research led by the Queen Mary team builds on this by studying the impact of knocking out baz1b gene function and the impact of doing so on neural crest development and social behaviour.

The mutant zebrafish studied were found to be more socially prone than their baz1b-functional counterparts. They showed a greater tendency to interact with members of the same species, although the differences between the two types of zebrafish were no longer observable once the fish was three weeks old.

In addition to being more social, the mutant zebrafish displayed distinctive facial changes in later life. These included altered eye length and width, a protruding forehead, and a shorter snout. This was accompanied by a reduction in anxiety-associated behaviors.

To measure this, the researchers examined the zebrafish’s response to a brief flash of light, specifically the distance traveled over a five-minute period after the flash, as well as their response to an acoustic startle and their response when exposed to a new light. setting. In all cases, the mutant zebrafish recovered more quickly after a change in condition, indicating less fear-related reactivity.

The mutant zebrafish also showed mild neural crest underdevelopment in the larval stages.

The research determined that in zebrafish, the baz1b gene affects morphological and behavioral characteristics associated with domestication syndrome in other species.

José Vicente Torres Pérez, co-author from Queen Mary University of London and the University of Valencia, said: “Since the process of self-domestication, which allowed modern humans to form social groupsAmong other features, it is similar to the domestication process in other ‘domesticated’ species, our research has the potential to help us unravel the biological roots that govern these behaviours.

“Our research supports the existing hypothesis that the morphological and behavioral changes that arose with domestication in animals and humans can be attributed to the underdevelopment of neural crest stem cells.”

Professor Caroline Brennan, lead author and Professor of Molecular Genetics at Queen Mary University of London, added: “This study offers an interesting perspective on the origins of how we interact with others. While carrying the zebrafish findings to other vertebrates can be a challenge comparative studies how these give insight into the evolution of human cognition”.

Zebrafish were chosen in part for the research because about 80% of genes associated with human disease have a corresponding ortholog: a gene in a different species that evolved from a different species. common ancestor—making the zebrafish an ideal model for studying the genetics and underlying behavior of neural circuitry.