Detection by Microsatellite Analysis of Early Embryonic Mortality in an Alligator Population in Florida

• Published in: Journal of wildlife diseases Vol. 38; no. 1; pp. 160 - 165
• Main Authors: Rotstein, David S., Schoeb, Trenton R., Davis, Lisa M., Glenn, Travis C., Arnold, Beverly S., Gross, Timothy S.
• Format: Journal Article
• Language: English
• Published: United States Wildlife Disease Association 01-01-2002; Wildlife Dis Assoc
• Subjects: Alleles; Alligator mississippiensis; Alligators and Crocodiles - embryology; Alligators and Crocodiles - genetics; Alligators and Crocodiles - physiology; American alligator; Animals; blastodisk; DNA; Embryo, Nonmammalian - drug effects; Embryo, Nonmammalian - physiology; Female; Fertilization; Florida; Freshwater; genetics; Genotype; Hydrocarbons, Chlorinated; Insecticides - toxicity; Male; Microsatellite Repeats - genetics; Mortality; Polymerase Chain Reaction - veterinary; Population Dynamics; Reproduction - drug effects; Sequence Analysis; Florida; USA, Florida, Apopka L
• ISSN: 0090-3558; 1943-3700
• DOI: 10.7589/0090-3558-38.1.160

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 with 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 micro-satellite 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.