Natural selection shaped the rise and fall of passenger pigeon genomic diversity

The now-extinct passenger pigeon used to be one of the most numerous vertebrates on Earth. Murray et al. examined the genomes of four passenger pigeon samples from different locales within its range. They describe the interplay between passenger pigeon population size, genome structure and recombination, and natural selection. They conclude that a reduction in genetic diversity provided few avenues for the bird to respond to human pressures, which ultimately drove it to extinction.