Consequences of a Genetic Bottleneck in California Condors: A Mitochondrial DNA Perspective

—The California Condor (Gymnogyps californianus) has recently survived a severe population bottleneck. The entire population was reduced to 27 individuals in 1982. The number of genetic founders was even smaller. We obtained 482 base pairs of DNA sequence from the mitochondrial control region (CR) of all founder individuals that poten­ tially represented unique maternal haplotypes. Four unique haplotypes were present in the genetic founders. One of these haplotypes is unique to Topatopa, a male brought into captivity in 1967, whose haplotype will not persist in the future population. Haplotype diversity (h) was reduced by 25% between the founder population and our census of the 2002 popula­ tion. Nucleotide diversity (θ) did not vary significantly between the founders and the current population. Our results provide insights into condor genetics. First, where recessive deleteri­ ous alleles have been expressed in progeny (e.g., chondrodystrophy) the breeding pair shares the same mitochondrial haplotype. Second, we identified the presence of a nuclear copy of the mitochondrial control region and provide condor specific primer sequences to preferentially amplify DNA of mitochondrial origin. Third, we confirm low levels of genetic diversity in the captive population as suggested by previous research. Forth, we question whether the low level of diversity is a consequence of the 20th century bottleneck, or if diversity has been historically low over a much longer time scale. California Condors (Gymnogyps californianus) are North America’s largest soaring birds. Condors inhabited much of the continental United States prior to European settlement (Simons 1983, Steadman and Miller 1986, Wilbur 1978). However, the range of the species had contracted to Biological Sciences Department, California Polytechnic State University, San Luis Obispo, California 93407, USA. 1Address correspondence to this author. E-mail: [email protected]