14. Role of Genetics in Conservation Biology
237
application of several probes provides levels of polymorphism comparable with
those from multilocus DNA fingerprinting, while also providing estimates of
heterozygosity (Jeffreys et al. 1990, 1991; Burke et al. 1991; Hanotte et al. 1992;
Scribner et al. 1994). However, the development of single-locus probes is timeconsuming and more expensive than multilocus probes, and hence quick screening with multilocus probes may be the best first step.
Microsatellite DNA (Tautz 1989; Weber and May 1989)
Microsatellites are tandem repeats of di-, tri-, or tetranucleotides that are a result
of mutation length changes and are found in many vertebrate species. As individual microsatellite arrays are relatively short, they can be amplified by using PCR
primers designed to anneal to the conserved flanking regions of each microsatellite “locus.” Subsequently, locus-specific microsatellite variation, or simple
sequence length polymorphism can be visualized through electrophoresis of the
marked PCR fragments (Burke et al. 1991; Schl¨ otterer et al. 1991; Bruford et al.
1992).
Like minisatellite DNA, microsatellites are inherited in Mendelian fashion, and
copy numbers of the repeat unit vary greatly within individuals at different loci
and among individuals of a population at the same locus. The level of variability
differs among microsatellite regions, offering an opportunity to select microsatellite loci that provide the appropriate level of resolution for a study. Microsatellite DNA fingerprinting is ideally suited for parentage analysis, as well as
providing allele frequencies essential for estimates of gene flow and genetic
diversity. In addition, this PCR-based method allows analysis of minute amounts
of DNA (e.g., from hair or fecal samples), providing unrivaled opportunities to
address questions of paternity and population genetics in wild animals (e.g., in
wild chimpanzees) (Morin and Woodruff 1992). Thus far, microsatellite DNA
fingerprinting has been less recommended for quick genetic assays of endangered
or threatened species, as suitable microsatellite primers are still not readily available and are labor intensive in development (Edwards et al. 1991; Moore et al.
1991; Rico et al. 1994). However, the probability of detecting variable microsatellite loci and hence their usefulness for conservation genetics has recently
increased significantly through the application of microsatellite-enriched genomic libraries (Armour et al. 1994; Fleischer and Loew 1996).
Mitochondrial DNA (Avise et al. 1987; Moritz et al. 1987;
Harrison 1989; Wolstenholme 1992; Simon et al. 1994)
Animal mtDNA is a circular molecule 15–20 kilo bases in length and contains
about 37 genes (coding for 22 mitochondrial transfer RNA genes [tRNA], two
rRNAs, and 13 proteins) and a control region associated with the molecule’s
replication and transcription. mtDNA is generally maternally inherited and
evolves relatively quickly due to the apparent lack of repair mechanisms for
237
application of several probes provides levels of polymorphism comparable with
those from multilocus DNA fingerprinting, while also providing estimates of
heterozygosity (Jeffreys et al. 1990, 1991; Burke et al. 1991; Hanotte et al. 1992;
Scribner et al. 1994). However, the development of single-locus probes is timeconsuming and more expensive than multilocus probes, and hence quick screening with multilocus probes may be the best first step.
Microsatellite DNA (Tautz 1989; Weber and May 1989)
Microsatellites are tandem repeats of di-, tri-, or tetranucleotides that are a result
of mutation length changes and are found in many vertebrate species. As individual microsatellite arrays are relatively short, they can be amplified by using PCR
primers designed to anneal to the conserved flanking regions of each microsatellite “locus.” Subsequently, locus-specific microsatellite variation, or simple
sequence length polymorphism can be visualized through electrophoresis of the
marked PCR fragments (Burke et al. 1991; Schl¨ otterer et al. 1991; Bruford et al.
1992).
Like minisatellite DNA, microsatellites are inherited in Mendelian fashion, and
copy numbers of the repeat unit vary greatly within individuals at different loci
and among individuals of a population at the same locus. The level of variability
differs among microsatellite regions, offering an opportunity to select microsatellite loci that provide the appropriate level of resolution for a study. Microsatellite DNA fingerprinting is ideally suited for parentage analysis, as well as
providing allele frequencies essential for estimates of gene flow and genetic
diversity. In addition, this PCR-based method allows analysis of minute amounts
of DNA (e.g., from hair or fecal samples), providing unrivaled opportunities to
address questions of paternity and population genetics in wild animals (e.g., in
wild chimpanzees) (Morin and Woodruff 1992). Thus far, microsatellite DNA
fingerprinting has been less recommended for quick genetic assays of endangered
or threatened species, as suitable microsatellite primers are still not readily available and are labor intensive in development (Edwards et al. 1991; Moore et al.
1991; Rico et al. 1994). However, the probability of detecting variable microsatellite loci and hence their usefulness for conservation genetics has recently
increased significantly through the application of microsatellite-enriched genomic libraries (Armour et al. 1994; Fleischer and Loew 1996).
Mitochondrial DNA (Avise et al. 1987; Moritz et al. 1987;
Harrison 1989; Wolstenholme 1992; Simon et al. 1994)
Animal mtDNA is a circular molecule 15–20 kilo bases in length and contains
about 37 genes (coding for 22 mitochondrial transfer RNA genes [tRNA], two
rRNAs, and 13 proteins) and a control region associated with the molecule’s
replication and transcription. mtDNA is generally maternally inherited and
evolves relatively quickly due to the apparent lack of repair mechanisms for