Maintenance of genetic variability in a specific pathogen-free breeding colony.

We used 18 genetic loci including blood groups, isozymes, and a serum protein to evaluate our efforts to preserve genetic variability in a specific pathogen-free (SPF) colony of rhesus monkeys. We compared genetic variability in the SPF population to the virally contaminated, non-SPF population from which it was derived. There was no change in the average gene diversity between the SPF and non-SPF populations. However, gene diversity at blood group Q locus increased significantly in the SPF population, while blood group M locus showed an insignificant trend toward decreased gene diversity. Allele frequencies changed significantly at blood group Q locus, although no alleles were lost from the population. We hypothesized that this change was due to extensive overreproduction by a small number of founder males that possessed the initially rare allele, Q1. There was no evidence that this change was associated with genes involved in viral infection.