“The Genetic Basis of Spatial Cognitive Variation in a Food-Caching Bird”, 2021-11-03 (; similar):
- Food-caching birds use spatial cognition to recover food stores and survive winter
Variation in cognitive phenotypes is associated with variation across the genome
Top outlier genes are associated with hippocampal development and function
Results link cognitive and genetic variation, making it available for selection
Spatial cognition is used by most organisms to navigate their environment. Some species rely particularly heavily on specialized spatial cognition to survive, suggesting that a heritable component of cognition may be under natural selection. This idea remains largely untested outside of humans, perhaps because cognition in general is known to be strongly affected by learning and experience.
We investigated the genetic basis of individual variation in spatial cognition used by non-migratory food-caching birds to recover food stores and survive harsh montane winters.
Comparing the genomes of wild, free-living birds ranging from best to worst in their performance on a spatial cognitive task revealed statistically-significant associations with genes involved in neuron growth and development and hippocampal function.
These results identify candidate genes associated with differences in spatial cognition and provide a critical link connecting individual variation in spatial cognition with natural selection.
[Keywords: spatial cognition, genome-wide, food-caching, genetic basis, natural selection]
…We used whole-genome sequencing, combining traditional genome-wide association studies (GWASs) and a Random Forest machine learning approach, to compare the genomes of wild, free-living birds. We sampled birds from high and low elevations that performed the best on a spatial cognitive task, all of whom survived more than one year (n = 22), to those that performed the worst on the task and generally did not survive more than 1 year (n = 15⁄20)—the group with better spatial cognition was associated with a statistically-significant survival advantage (Fisher’s exact test, p < 0.001). Birds from both high and low elevations were selected for each performance group to ensure that the strongest signal between groups was variation in cognition and not a correlate of elevation…We sampled 42 mountain chickadees across 3 years of testing from the extremes of the cognitive performance range: 22 were chosen as the best and 20 were chosen as the worst. Performance scores of individuals in the best and worst groups did not overlap, but individual variation within each group provided a continuous distribution from best to worst (Figure 1F). We intentionally chose individuals with means in the tails of the cognitive performance distribution (Figures 1E & 1F) to amplify the signal of genetic associations, although we acknowledge that this design could inflate associations from loci with the largest effect to the detriment of small-effect polygenes. There was a statistically-significant difference in the mean number of errors per trial between best (mean errors/trial: 0.16 ± 0.045) and worst (0.60 ± 0.05) performers (cognitive category [best versus worst]: F1,38 = 72.91, p < 0.0001; Figure 1F), but there was not a statistically-significant effect of elevation, as we selectively picked the best and worst performers at each elevation (elevation [high versus low]: F1,38 = 1.38, p = 0.247; total trials completed [covariate]: F1,38 = 5.26, p = 0.028).