Degree Type


Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Elliot S. Krafsur


Single strand conformation polymorphisms (SSCP) were surveyed in 111 natural housefly populations (ca. 2400 flies) from Wallace's zoogeographical regions including the Nearctic, Neotropical, Ethiopian, Oriental, Australian, and Palearctic. The resolution of SSCP was evaluated by analyzing nucleotide diversities within and between SSCP phenotypes. The efficacy of analyzing frequency data on gel phenotypes at eight loci and on haplotypes formed by combining alleles at two, three, four, five, and eight loci was examined.;The resolution achieved with the SSCP method was estimated to be 64% of available nucleotide variation at the loci studied. Haplotypes formed by alleles at two loci were as informative about population structure as haplotypes composed of a greater number of loci. Increasing the number of loci above two increased diversity estimates within populations only. The two most variable and consistently amplifiable loci (16S2 and COII ) were then chosen to survey diversity in all populations.;Forty-eight haplotypes were detected. No haplotype was ubiquitous, and 24 (55%) were confined to a single zoogeographical region. The regional diversity indices HS were heterogeneous. The differentiation among regions GST was 0.49 and differentiation within regions GPR was 0.32, indicative of a high degree of population structuring.;In the New World the number of haplotypes and gene diversities were homogeneous among the six subregions examined, but a strong spatial component was found in the distribution of haplotypes, particularly in the Nearctic. Nei's differentiation index GRT was 0.53 among subregions. Most (69%) of the variance of haplotype frequencies was attributed to differences among populations within subregions. Greater differentiation was found among populations in the Nearctic than in the Neotropics.;The research indicated high degrees of structuring at all hierarchical levels thus suggesting low rates of maternal gene flow, a surprising result considering the great vagility of house flies and the opportunities for distribution via commercial transport.



Digital Repository @ Iowa State University,

Copyright Owner

Jose Gerardo Marquez



Proquest ID


File Format


File Size

132 pages

Included in

Entomology Commons