Microsatellite DNA Diversity and Paternity Determination in a Captive Population of Radiated Tortoises (Geochelone radiata)
Date of Award
Master of Science (MS)
Richard R. Montanucci
In the present study, five microsatellite loci are used to examine genetic diversity and determine genetic similarities among 66 radiated tortoises (Geochelone radiata) located in ten different zoos and institutions in the United States. These tortoises, representatives of one of the world's most endangered species, were originally collected in Madagascar and are being used as founders in the development of an organized breeding program, the radiated tortoise Species Survival Plan (SSP). Parentage analysis was also conducted for 13 juvenile tortoises of uncertain parentage from two institutions. Founder tortoises demonstrated high levels of genetic diversity at the five loci examined. Furthermore, neighbor-joining analysis revealed that there are seven male/female pairs being held within the same institution that may be undesirably genetically similar. Genetically similar tortoises could produce inbred progeny that might experience decreased fitness. Parentage analysis revealed that paternity of the juveniles was often incorrectly assigned when based on simple observation. These results are important for future management of this species. The SSP for radiated tortoises was initiated by the American Zoo and Aquarium Association in 1985 to manage the captive population of tortoises located in various institutions for long term survival. Managing a captive population for retention of genetic diversity and inbreeding avoidance requires knowledge of founder relationships and precise pedigree maintenance. Current management schemes can be adjusted to take into account genetic similarity between founders and to minimize errors in parentage assignments in order to avoid inbreeding. Incorrect assignments of paternity will skew calculations of founder contributions to the SSP population and eventually corrupt the entire SSP pedigree.
Mook, Jennifer Leigh, "Microsatellite DNA Diversity and Paternity Determination in a Captive Population of Radiated Tortoises (Geochelone radiata)" (2000). All Theses. 3628.