Behavioural analysis of loss of function zebrafish supports baz1b as master regulator of domestication

Abstract

Domestication is associated with both morphological and behavioural phenotypic changes that differentiate domesticated species from their wild counterparts. Some of the traits are those purposely targeted by the selection process, whilst others co-occur as a result of selection. The combination of traits is referred to as the domestication syndrome and their shared characteristics has given rise to the neural crest domestication syndrome (NCDS) hypothesis. According to this hypothesis, the phenotypic changes are a consequence of a selection towards animals with mild underdevelopment of the neural crest. A similar mechanism is suggested to affect some species of self-domesticated animals, including humans. Recent research supports a role for BAZ1B, one of the haplo-insufficient genes in Williams syndrome (WS), in the evolution of craniofacial features of modern humans. Interestingly, WS recapitulates some of the traits observed in the domestication syndrome, including hypersociability and reduced facial bones. However, the evidence linking BAZ1B to behavioural phenotypes associated with domestication is presumptive. Here, we use zebrafish as a model to test the hypothesis that baz1b loss-of-function leads to both morphological and behavioural phenotypes associated with the domestication syndrome by influencing the development of the neural crest. Our research provides further evidence supporting the NCDS hypothesis and baz1b's role in this process.

Fish as Model Systems to Study Epigenetic Drivers in Human Self-Domestication and Neurodevelopmental Cognitive Disorders

“…Recently, the hypothesis was empirically validated and the role of BAZ1B , a gene within the hemideleted region in WS with an established role in neural crest induction and migration, was demonstrated [ 13 ]. The implication of this gene in morphological and behavioral phenotypes typical of the domestication syndrome via neural crest cell development was further shown using zebrafish as a model [ 74 ]. Our comparative results between AMHs and early European sea bass domesticates provide additional support for the role of specific genes in key processes with an impact on (self-)domestication features and suggest a role for epigenetic regulation of their expression.…”

“…RUNX2 encodes a master transcription factor during vertebrate development involved in the globularization of the human skull/brain. RUNX2 is also involved in the development of thalamus, which is functionally connected to many genes that are important for brain and language development, and that have experienced changes in our recent evolutionary history [ 74 ]. NCOR2 has already been identified as under selection in dogs [ 69 ], and is part of the cranial neural crest gene expression program [ 82 ].…”

“…A recent study using zebrafish investigated the role of neural crest in the morphological and behavioral domesticated phenotypes in [ 13 ] HSD. They found that a loss of function of the key gene in WS and for the neural crest, baz1b , identified as important previously in humans as well [ 13 ], resulted in mild neural crest deficiencies during development and behavioral changes related to stress and sociality in adulthood [ 74 ]. Furthermore, comparative genomics using domesticated mammals have already been used to shed light to the HSD hypothesis [ 12 ].…”