Genetic Management of Groups

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Genetic diversity is essential for the long- and short-term survival of populations and individuals. Some of the most intense genetic management occurs in captive populations where breeding programs involve specific breeding recommendations for every individual in the population. The current strategy used by captive breeding programs worldwide to minimize loss of genetic diversity pairs individuals according to a mean kinship (MK) value. MK requires both knowledge of the population's pedigree and control over which pairings are made. This strategy is practical for many of the large species managed in captivity, but is unrealistic for species for which there is insufficient information or over which we have less control. These include certain species of captive animals that are not maintained individually (e.g., herds of antelope) and populations in the wild. Populations such as these, where detailed pedigree information is unknown, ages and individuals are difficult to identify, and/or specific pairings cannot reliably be made, are referred to as "groups". I propose a strategy for managing groups that involves manipulating population structure, migration rates, and the tenure of breeding males. I found that group management does carry a genetic cost relative to MK-based management, and that cost will need to be weighed against the financial costs of managing animals at the individual level as opposed to the population level. Group management is better than no management and may provide an option for genetic management of currently "unmanageable" captive populations (e.g., tanks of fish), global captive populations, and wild populations. I also tested the robustness of an MK-based management strategy. A kinship-based breeding strategy is modeled with all breeding recommendations being followed. However, this idealized scenario does not always occur. I found genetic diversity does decrease as breeding recommendations are not followed. This includes the breeding of overrepresented (High MK) animals that are recommended to not breed and the reduced success of Low MK animals that are recommended to breed. The robustness of MK is dependent upon the species being managed. These results should be factored into any cost/benefit analysis of individual and group management strategies.