Scientists involved in conservation genetics come from a variety of fields including population genetics, research in natural resource management, molecular ecology, molecular biology, evolutionary biology, and systematics.
Genetic diversity on the population level is a crucial focus for conservation genetics as it influences both the health of individuals and the long-term survival of populations: decreased genetic diversity has been associated with reduced average fitness of individuals, such as high juvenile mortality, reduced immunity,[2] diminished population growth,[3] and ultimately, higher extinction risk.
This lower heterozygosity (i.e. low genetic diversity) renders small populations more susceptible to the challenges mentioned above.
High homozygosity (low heterozygosity) reduces fitness because it exposes the phenotypic effects of recessive alleles at homozygous sites.
Selection can favour the maintenance of alleles which reduce the fitness of homozygotes, the textbook example being the sickle-cell beta-globin allele, which is maintained at high frequencies in populations where malaria is endemic due to the highly adaptive heterozygous phenotype (resistance to the malarial parasite Plasmodium falciparum).
For example, mitochondrial DNA in animals has a high substitution rate, which makes it useful for identifying differences between individuals.
In plants, the mitochondrial DNA has very high rates of structural mutations, so is rarely used for genetic markers, as the chloroplast genome can be used instead.
Other sites in the genome that are subject to high mutation rates such as the major histocompatibility complex, and the microsatellites and minisatellites are also frequently used.
These techniques can provide information on long-term conservation of genetic diversity and expound demographic and ecological matters such as taxonomy.
Historic DNA is important because it allows geneticists to understand how species reacted to changes to conditions in the past.
[15] Techniques using historic DNA include looking at preserved remains found in museums and caves.
[17]This too avoids disrupting the animals and can provide information about the sex, movement, kinship and diet of an individual.
[14] Hybridization is an especially important issue in salmonids and this has wide-ranging conservation, political, social and economic implications.
In analysis of its mtDNA and alloenzymes, hybridization between native and non-native species has been shown to be one of the major factors contributing to the decline in its populations.
More recent applications include using forensic genetic identification to identify species in cases of poaching.