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newly establishing population does not need as many founders to
replicate the frequency distributions occurring in the source population
(including the capture of all unique alleles). Thus, it has been noted that the
aforementioned 50/500 rule is meant only as a very general guideline. The
number of founders needed, and target sustained population size, will differ
for populations with different source population loci architectures and,
as demonstrated below, different life history characteristics. Many of the
models and commonly used teaching examples used to discern population
genetics principles in small populations involve loci with fewer alleles of
higher frequencies and comparatively simple life history characteristics
compared to many of the examples given below.
The above trials discussed cases in which the conservationist wants
to ensure that at least one copy of every unique allele in the source
population is captured by the founding population. Obviously, however,
several factors may affect whether unique alleles at the lowest frequency
among the founders are retained as the population develops (examples
of factors are explored below). Some of these factors may be predictable
and thus manageable, but others may be stochastic. Therefore, founding
populations with numbers well above the minimum needed to capture all
source population unique alleles are usually recommended (see also Brown
and Hardner 2000).
Introductions and preservation of genetic diversity will thus take
many forms. All of the above considerations are noted to emphasize that
NEWGARDEN facilitates the study of the effects of founding conditions on
genetic diversity retention. In the following sections, sample trials in which
some variables are changed over a range while others are held constant are
given to demonstrate how NEWGARDEN is used as well as how such trials
can illuminate population genetics and diversity conservation principles.
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