Man's Best Friend: A Biological Basis?

Researchers in Sweden have undertaken one of the first projects of its kind, to identify the biological basis for the connection between humans and dogs. To conduct this ambitious experiment, researchers first conducted human-directed behavior tests on a group of 437 laboratory beagles. The beagles were placed in a room with three lidded containers containing treats, and a human participant. The first two containers were designed to be opened easily, but the third was tightly sealed. The dogs were rated on their attempts to seek human help in opening the third container. The primary measures for this were duration of human proximity and duration of human contact. The top 95 and low 95 performers on this task (those who sought out humans the most and least) were then subjected to a GWAS study in which they were SNP genotyped. Researchers then compared SNP genotypes at each locus with performance on the behavior tests. The resulting Manhattan plots are shown here:


Four significant SNP loci were found to be associated with seeking human interaction, two were located within the same gene. The genes found to be significantly linked with these behaviors were SCZ6L, ARVCF, and, less significantly, TXNRD2, COMT and TANGO2. Researchers discovered that these genes were also known to be associated with social behaviors and disorders in humans. SCZ6L has been associated with autism, and ARVCF, COMT, and TXNRD2 have been associated with schizophrenia. COMT polymorphisms have additionally been associated with mood regulation and aggressive behavior in those with ADHD. This research is important because it reveals more about the genetic basis of human and dog relationships, and therefore more about breeding and domestication practices. Researchers also suggest that the discovery of the same genes linked with social behavior in humans could be useful for using dogs to understand more about human social behaviors. 
Sources: 
https://www.theguardian.com/science/2016/sep/29/secret-of-connection-between-dogs-and-humans-could-be-genetic
http://www.nature.com/articles/srep33439