SREL Reprint #2648

Detection by microsatellite analysis of early embryonic mortality in an alligator population in Florida

David S. Rotstein1, Trenton R. Schoeb2, Lisa M. Davis3,4, Travis C. Glenn3,4, Beverly S. Arnold5, and Timothy S. Gross1,5

1College of Veterinary Medicine, Department of Physiological Sciences, University of Florida,
Gainesville, Florida 32610, USA
2College of Veterinary Medicine, Department of Pathobiology, Division of Comparative Medicine,
University of Florida, Gainesville, Florida 32610, USA
3Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA 4Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, South Carolina 29802, USA
5United States Geological Survey-Biological Resources Division, Florida Caribbean Science Research Center, Gainesville, Florida 32653, USA

Abstract: In the 1980s, alligators (Alligator mississippiensis) of Lake Apopka (Florida, USA) underwent a population decline associated with decreased egg viability, effects that have been associated endocrine-disrupting, persistent organochlorine pesticides. It is currently unknown whether the decreased egg viability is due to fertilization failure or early embryonic death. Therefore, we conducted a preliminary study to evaluate the use of microsatellite DNA loci to determine the fertilization status of nonviable eggs. Using microsatellite analysis, we compared genotypes from blastodisks and embryos with the genotypes from females trapped at the nest. Four of five nonviable egg samples tested yielded evidence of fertilization. No evidence of unfertilized eggs was obtained, but amplifiable DNA could not be obtained from one entirely nonviable clutch. Thus, we demonstrate that early embryonic mortality in alligators can be detected by microsatellite analysis, but also suggest substantial effort is needed to improve the recovery of DNA and amplification of alligator microsatellite loci.

Keywords: American alligator, Alligator mississippiensis, blastodisk, DNA, fertilization, genetics

SREL Reprint #2648

Rotstein, D. S., T. R. Schoeb, L. M. Davis, T. C. Glenn, B. S. Arnold, and T. S. Gross. 2002. Detection by microsatellite analysis of early embryonic mortality in an alligator population in Florida. Journal of Wildlife Diseases 38:160-165.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).