Genetic Structure and Variability in the Green Iguana (Iguana iguana)

A population of green iguanas (Iguana iguana) that inhabits the forests around Gatun Lake in central Panama faces an apparent scarcity of suitable nesting sites. To investigate whether the disjunct distribution of nesting sites in this area and strong nesting site fidelity by female iguanas has contributed to genetic structuring of the population, samples obtained from females captured at three main nesting sites were analyzed electrophoretically. Significant allele frequency differences existed among nesting sites at one of the two polymorphic loci inspected. The pattern of allele frequency differences was consistent with what is known of iguana movement patterns and suggests that the genetic structure of the population has been influenced by nesting site availability and distribution. Additional electrophoretic analyses were conducted on samples obtained from three iguana populations from central Panama, western Panama, and Venezuela. Low levels of heterozygosity and polymorphism were observed in each of these populations, yet significant differences at three polymorphic loci were demonstrated. The management implications of the results are discussed.