Biology Reference
In-Depth Information
7
CHAPTER
Founder Number and Allelic
Diversity
In the following sections and chapters, sample NEWGARDEN trials
are compared to demonstrate how some of the types of input data and
user-specifi ed conditions described above are used in practice, and how
comparative trials can be informative. This chapter focuses on very simple
trials to demonstrate some of the basic concepts. More details concerning
programming statements are given early on to help readers learn how to
use NEWGARDEN. Since there are several different aspects of input fi les
that can be changed, some of which are continuous variables, there are a
large number of permutations of possible combination of conditions, and
we cannot explore them all. However, it is hoped that the following limited
examples will not only familiarize users with the potential applications of
NEWGARDEN, but also provide new insights into reintroduction processes
and their effect on genetic diversity. For the sample trials, usually the
complete initial data input for only the fi rst, or basic, trial is given. After the
basic fi le is presented, for parallel comparative trials, only specifi c variables
that are altered in such derivative trials are noted.
How Many Founders: Loci Arrays and Founder Effects
In studying the population genetics of establishing populations, estimation
of the intensity of the founder effect is central to investigating differences
in genetic diversity under alternative population development scenarios.
For example, NEWGARDEN can be used to examine how founding events
of different sizes can affect the genetic diversity of the initial colonizing
population across multiple loci with identical or differing allelic frequency
distributions.
A land manager attempting to reintroduce a species at a site will
generally want to introduce as much of the source genetic variation as
possible. Should she introduce 100 individuals? 1000 individuals? The
former choice may be more economical, but using fewer individuals may
incur a greater founder effect, depending on the allelic diversity and history
of the source population.
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