Theses and Dissertations


Jamen W. Berk

Issuing Body

Mississippi State University


Welch, Mark E.

Committee Member

Wallace, Lisa

Committee Member

Gerber, Glenn P.

Date of Degree


Document Type

Graduate Thesis - Open Access


Biological Sciences

Degree Name

Master of Science (M.S.)


College of Arts and Sciences


Department of Biological Sciences


Inbreeding depression affects captive populations and those that have been recently impacted by anthropogenic disturbance. However, the evolutionary importance of inbreeding depression in natural populations is not well understood. This study focuses on a naturally small population of Cyclura carinata, the Turks and Caicos Rock Iguana, that has likely been stable for hundreds of generations. Genotypic data at 13 polymorphic microsatellite loci, along with fitness proxies, were collected from 188 individuals across three age classes. Multi-locus heterozygosity is strongly predictive of age class (p < 0.03), and is significantly lower in hatchlings than in juveniles or adults. Estimates for intensity of selection favoring heterozygosity range from 0.498-0.627, indicating that this proportion of individuals fail to survive due to inbreeding depression. The heterozygosityitness correlation among adults is significant (p < 0.01), suggesting outbred individuals have higher reproduction success. Hence, the lifetime influence of inbreeding on fitness is extremely high.