Data from: Genomic regions underlying metabolic and neuronal signaling pathways are temporally consistent outliers in a moving avian hybrid zone

The study of hybrid zones can provide insight into the genetic basis of
species differences that are relevant for the maintenance of reproductive
isolation. Hybrid zones can also provide insight into climate change,
species distributions, and evolution. The hybrid zone between black-capped
chickadees (Poecile atricapillus) and Carolina chickadees (P.
carolinensis) is shifting northward in response to increasing winter
temperatures but is not increasing in width. This pattern indicates strong
selection against chickadees with admixed genomes. Using high-resolution
genomic data, we identified regions of the genomes that are outliers in
both time points and do not introgress between the species; these regions
may be involved in the maintenance of reproductive isolation. Genes
involved in metabolic regulation processes were overrepresented in this
dataset. Several gene ontology categories were also temporally
consistent—including glutamate signaling, synaptic transmission, and
catabolic processes—but the nucleotide variants leading to this pattern
were not. Our results support recent findings that hybrids between
black-capped and Carolina chickadees have higher basal metabolic rates
than either parental species and suffer spatial memory and problem-solving
deficits. Metabolic breakdown, as well as spatial memory and
problem-solving, in hybrid chickadees may act as strong postzygotic
isolation mechanisms in this moving hybrid zone.