One of the most striking features of dogs is that they are friendlier to humans than wolves, a result of genetic changes that occur during domestication, according to an ELTE announcement sent to MTI.
As written,
Extreme innate friendliness also occurs between people, particularly among people with Williams-Beuren syndrome.
Additionally, a similar genetic defect has been identified in the genomes of dogs and people with Williams syndrome.
“The GTF2I gene is involved in regulating the development of the nervous system, and exerts its influence mainly in neural pathways related to anxiety and affection. In our current research, we wanted to investigate whether different versions of the gene lead to different spatial chromatin structures,” Bridget von Holdt, a researcher at Princeton University and lead author of the paper published in BMC Genomics, detailed in the announcement.
“Chromatin is the name for the DNA and protein complex that makes up chromosomes. There are several versions of the GTF2I gene. Wolves carry a different one than most dogs. If different gene variants modify the spatial organization of chromatin, that could also affect gene activity,” he added.
The researchers needed dog brain tissue for the study, so they contacted the staff of the Dog Brain and Tissue Bank of the ELTE Department of Ethology. Dogs that were euthanized for health reasons, mostly of advanced age, are placed in the tissue bank on the basis of donations from farmers. In this study, we only included dogs that did not suffer from a disease of the nervous system – explained Eniko Coppini, head of the department, who founded the bank together with geneticist Sara Sandor and veterinarian Kalman Schippert in 2017.
The results confirmed expectations, because the old and new versions of the GTF2I gene lead to different chromatin organization.
“Self-replicating mobile gene segments, called retrotransposons, are often incorporated into DNA. This segment was incorporated into the ancient version of the GTF2I gene, but was co-opted from the modern dog genome. We found that the presence or absence of the retrotransposon changes the three-dimensional structure of the chromatin surrounding the GTF2I gene. If the segment is missing, the chromatin loop does not form when the DNA is packaged. This changes gene expression, which may partly explain the difference in dog and wolves’ behavior,” concluded Dhriti Tandon, the study’s first author.
Based on the results, the hypersocial behavior of dogs and humans appears to have a similar molecular background, the researchers concluded.
When it turns out that dogs carry different genetic variants than wolves, it can be assumed that the difference has evolutionary significance.
– Eniko Coppini, who believes that their realization that not only the primary sequence of DNA, but also the spatial structure associated with proteins can contribute to the development of behavior, could give a new direction to dog evolutionary research.
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