Published in Integrative and Comparative Biology, the study by Gitanjali E. Gnanadesikan, Brian A. Hare, E. MacLean, and colleagues leverages the extraordinary phenotypic and behavioral diversity of dog breeds to explore how genetics contributes to variation in cognition. Prior work showed that genetic relatedness among breeds explains a substantial portion of cognitive differences; this study dives deeper into the specific genetic architecture behind those patterns.
The team combined cognitive test data from 1,654 dogs across 49 breeds, collected through the Dognition.com citizen science platform, with published breed-average genetic polymorphism datasets. They conducted a breed-average genome-wide association study (GWAS) examining four cognitive domains: inhibitory control, communication, memory, and physical reasoning.
Five single nucleotide polymorphisms (SNPs) reached genome-wide significance after Bonferroni correction. These SNPs were located in or near EML1, OR52E2, HS3ST5, a U6 spliceosomal RNA, and a long non-coding RNA. Each represents a promising candidate for understanding how specific genetic variants contribute to cognitive performance across breeds.
Expanding beyond single variants, the researchers aggregated results across multiple SNPs within genes and identified 188 genes associated with breed differences in cognition. This gene set was enriched for genes that are differentially expressed in brain tissue and involved in key neurological pathways, including Wnt signaling, peripheral nervous system development, presynapse assembly, and synaptic vesicle exocytosis.
These findings highlight that complex cognitive traits are influenced by numerous genetic factors, many of which are active in neural development and synaptic communication. By pinpointing specific variants and pathways, the study opens avenues for future research exploring how genetics shapes the remarkable diversity of cognitive abilities observed across dog breeds.
Source: Gnanadesikan, G. E., Hare, B. A., MacLean, E., et al. (2020). Breed Differences in Dog Cognition Associated with Brain-Expressed Genes and Neurological Functions. Integrative and Comparative Biology. Published July 29, 2020.
