Alfieri, James Michael (2023-07). The Role of Hybridization and Selective Breeding in Generating Diversity in Galliformes. Doctoral Dissertation.
Thesis
Gene flow and selection are two of the major evolutionary forces that generate life's diversity. Interspecies hybridization and selective breeding represent extreme cases of these two major evolutionary forces. Utilizing these extreme cases, I sought to further understand factors affecting both within- and between-species diversity in landfowl (Order: Galliformes). My first dissertation project sought to confirm the parentage of the most diverged avian hybrid, reported to be Rusty-margined guan (Penelope superciliaris) and Helmeted Guineafowl (Numida meleagris). Using ancient DNA extraction methods and whole-genome short-read sequencing, combined with phylogenetic and sequence similarity analyses, I determined that the most diverged avian hybrid is actually between the chicken (Gallus gallus) and Helmeted Guineafowl (Numida meleagris). My second dissertation project sought to explain the variance in the accumulation of reproductive isolation between species of Galliformes. Using a literature synthesis approach, I found that domestication is associated with an increase in reproductive compatibility, suggesting that the disruption in selective reproductive regimes impacts speciation in Galliformes. My final dissertation project sought to characterize the association between genetic diversity and the conservation status of heritage chicken breeds - typically the characterization of conservation status is a laborious process based on demographic data and expert opinions. Using whole-genome short-read sequencing, I determined that breeds at risk of extinction have lower genetic diversity than breeds not at risk. This study suggests that genetic surveys of breeds may be an accurate alternative to costly and time-consuming demographic census studies. Overall, the projects within this dissertation illustrate human's conscious and unconscious selection on Galliformes, which has shaped the genetic diversity of this clade.
