Racing pigeons have increased athleticism and navigational skills, but a genomic analysis conducted by researchers from the University of Porto in Portugal found no alleles that distinguish them from other breeds.
Porto's Miguel Carneiro and his colleagues sequenced the genomes of eight racing pigeons and combined them with data from two other already sequenced racing pigeons, 37 other birds belonging to 35 breeds — including fancy and utility breeds — and one outgroup. As they report in Molecular Biology & Evolution, the researchers examined the population structure of the pigeons as well as genome-wide patterns of allele frequency. While they found that racing pigeons are closely related, few genetic changes were specific to them. The researchers also noted that signatures of position selection were presennt across the racing pigeons' genomes, which they said suggested a polygenic basis for the birds' abilities.
When Carneiro and his colleagues folded in RNA sequencing data from the pigeons, they uncovered modest differences in muscle and brain gene expression between the types of birds.
"It is unlikely that any single genetic change is sufficient to account for the superior flight and orientation abilities of racing pigeons. In addition, we recovered a considerable number of signatures of selection across the genome, indicating a polygenic basis for the adaptations to extreme performance in this breed," Carneiro says in a statement at Phys.Org.