Grantee Research Project Results
Causes and Consequences of Hybridization Between California and Gambel's Quail (Callipepla californica and C. gambelii)EPA Grant Number: U915729
Title: Causes and Consequences of Hybridization Between California and Gambel's Quail (Callipepla californica and C. gambelii)
Investigators: Gee, Jennifer M.
Institution: Princeton University
EPA Project Officer: Manty, Dale
Project Amount: $102,000
RFA: STAR Graduate Fellowships (2000)
Research Category: Fellowship - Zoology , Academic Fellowships , Biology/Life Sciences
The objectives of this research project are to: (1) investigate inbreeding avoidance, which may be currently responsible for hybridization; (2) examine whether limited conspecific mate availability may have driven hybridization in the past; and (3) describe the genetic structure of California and Gambel's Quail to assess the impact hybridization may have on the fate of these species.Approach:
The magnitude of gene exchange between hybridizing species is determined by two factors: (1) the occurrence of heterospecific pairing; and (2) the survival and reproduction of hybrid genotypes. This proposal will investigate two hypotheses about breakdown barriers to gene flow between Gambel's and California Quail. It also will outline the measures that I am using to investigate the fitness consequences of hybridization. Given the conditions for breakdown to barriers to gene flow and hybrid fitness measures, I will examine the historical pattern of genes that have broken down between species and permitted increased species contact (Sumner, 1935). If the band of gene exchange is broad, species may be losing their distinctiveness and becoming a single panmictic population. Likewise, a narrow band of introgression may support that a sharp narrow cline exists between species signifying either recent secondary contact between species or strong selection against hybrids (Endler, 1977). Quails are sedentary, and typically move less than 5 miles during the course of their lives, but some individuals have been trapped more than 20 miles from where they were banded (Williams, 1959). Dispersal increases the potential for a wider geographic range of introgression than the narrow zone of sympatry would suggest.
I have sequenced mtDNA from the most distantly sampled areas in each species, and am using software packages designed to compare DNA sequences (such as PAUP). I am identifying fixed-species differences in a segment of cyt b approximately 1,000 base pairs long. Using restriction enzymes, I will develop a molecular assay that will identify mtDNA haplotypes unique to each species based on species-specific mtDNA fragment lengths. If female Gambel's Quail are underrepresented in all areas of species overlap, mtDNA should have introgressed further into the California Quail range than California Quail mtDNA introgressed into Gambel's Quail.Supplemental Keywords:
fellowship, Callipepla cailfornica, hybridization, molecular assay, mate availability, inbreeding avoidance, California Quail, Gambel's Quail.