Term of Award

Summer 1995

Degree Name

Master of Science in Biology

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Committee Chair

William S. Irby

Committee Member 1

James H. Oliver, Jr.

Committee Member 2

Sara Neville Bennett


Isozyme analysis using polyacrylamide gel electrophoresis was used to study the genetic structure of populations of three species of ticks Ixodes scapularis, Ixodes pacificus, and Dermacentor variables. Ixodes scapularis from Maryland, Massachusetts, and Georgia were compared to /. pacificus from California and D. variablis from Georgia which served as outgroups Small samples of /. scapularis from New York. Michigan, and Minnesota were also examined. Nine enzymes were resolved and 12 loci were identified. Using Ayala's 0.95 criterion, the percentage of polymorphic loci in /. scapulari ranged from 50 to 17%. and was 42% in I. pacificus, and 8% in D. variablis. Heterozygosity levels for all tick populations, with the exception of NY. MI, and MO, rellected normal genetic diversity. Nei's genetic identities for /. scapularis populations fell within the ranges expected for conspecific organisms, identity values for I. scapularis and /. pacificus fell within the range of congeneric organisms, and showed that the Ixodes populations were only distantly related to D. variables.