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15
Modeling Problems in Conservation
Genetics Using Laboratory Animals
Richard Frankham
Introduction
The biological diversity of the planet is rapidly being depleted. Loss of habitat,
overexploitation, pollution, and introduced species are threatening the survival of
an ever-increasing number of species. Consequently, many species require human
intervention to save them from extinction or at least to optimize their management. Intervention may take the form of habitat protection, habitat restoration,
reduction of exploitation, control of predators and diseases (usually introduced),
captive breeding, reintroduction, and translocation.
The critical genetic issues in the management of threatened, rare, and endangered species are
1. Inbreeding depression
2. Loss of genetic variation in small populations
3. Fragmentation of populations and reduction in migration
4. Genetic adaptation to captivity and its effect on reintroduction success
5. Taxonomic uncertainties that confound the objectives of conservation efforts.
For issues 1– 4, there is considerable theory that has been used in the genetic
management of rare and endangered species. However, this theory is typically
simple single locus neutralist theory that ignores natural selection, mutation, and
linkage. It is notable that experimental studies have shown significant deviations
from the predictions of related theory on the relationship between inbreeding and
heterozygosity (Mina et al. 1991; Rumball et al. 1994).
Consequently, it is critical that theory underlying genetic management of endangered species be subject to experimental evaluation. However, endangered
species are unsuitable for such research as typically they are present in low
numbers and are expensive to maintain. Further, their reproduction is often slow
and difficult to manage. Laboratory species provide an essential link between
theory and wildlife in the field. They have all the realistic genetic variables that
are absent in most theoretical models (mutation, migration, natural selection, and
linkage), and their reproduction can be controlled so that theory can be adequately
15
Modeling Problems in Conservation
Genetics Using Laboratory Animals
Richard Frankham
Introduction
The biological diversity of the planet is rapidly being depleted. Loss of habitat,
overexploitation, pollution, and introduced species are threatening the survival of
an ever-increasing number of species. Consequently, many species require human
intervention to save them from extinction or at least to optimize their management. Intervention may take the form of habitat protection, habitat restoration,
reduction of exploitation, control of predators and diseases (usually introduced),
captive breeding, reintroduction, and translocation.
The critical genetic issues in the management of threatened, rare, and endangered species are
1. Inbreeding depression
2. Loss of genetic variation in small populations
3. Fragmentation of populations and reduction in migration
4. Genetic adaptation to captivity and its effect on reintroduction success
5. Taxonomic uncertainties that confound the objectives of conservation efforts.
For issues 1– 4, there is considerable theory that has been used in the genetic
management of rare and endangered species. However, this theory is typically
simple single locus neutralist theory that ignores natural selection, mutation, and
linkage. It is notable that experimental studies have shown significant deviations
from the predictions of related theory on the relationship between inbreeding and
heterozygosity (Mina et al. 1991; Rumball et al. 1994).
Consequently, it is critical that theory underlying genetic management of endangered species be subject to experimental evaluation. However, endangered
species are unsuitable for such research as typically they are present in low
numbers and are expensive to maintain. Further, their reproduction is often slow
and difficult to manage. Laboratory species provide an essential link between
theory and wildlife in the field. They have all the realistic genetic variables that
are absent in most theoretical models (mutation, migration, natural selection, and
linkage), and their reproduction can be controlled so that theory can be adequately