Chapter 12
Mating and Mutation of Alleles
There is such an unerring power at work, or Natural Selection,
which selects exclusively for the good of each organic being.
(Darwin, Letters, 1857)
12.1 Model of Mating and Mutation of Alleles
Genetic theory provides us with insight into the changes of the genetic makeup of
organisms. These insights are of particular interest in the context of conservation
biology where genetic diversity is seen as one advantage of a species to survive in a
changing environment. The more different genetic information is present, the better
prepared a species to deal with a range of environmental factors.
Several processes influence the genetic makeup of organisms in a species. Among
those influences is the combination of various alleles into a genotype from “parents”
that carry those alleles. Another factor determining genetic makeup is the random
mutations of one type of allele into another. These two cases are dealt with in the
model of this chapter. The following chapter will then explore the impacts of natural
selection and fitness in conjunction with mutation on genotype distribution.
To model the process of genotype mixing and mutation we restrict ourselves—
without loss of generality—to the case of two alleles A and B, which are drawn
randomly from an initial pool of 200 A alleles and 300 B alleles. The results of the
simple mating of two alleles are explained by the Hardy–Weinberg law: this law
states that the genotype frequencies are determined in a random mating process.
These genotype frequencies are for AA, p^2; for AB, 2 * p * q; for BB, q^2, where p
and q are the A and B allele frequencies, respectively. In our sample problem,
p ¼ 200/500 or 0.4 and q ¼ 300/500 or 0.6 for our initial pool of 200 A alleles and
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_12,
© Springer International Publishing Switzerland 2014
99
Mating and Mutation of Alleles
There is such an unerring power at work, or Natural Selection,
which selects exclusively for the good of each organic being.
(Darwin, Letters, 1857)
12.1 Model of Mating and Mutation of Alleles
Genetic theory provides us with insight into the changes of the genetic makeup of
organisms. These insights are of particular interest in the context of conservation
biology where genetic diversity is seen as one advantage of a species to survive in a
changing environment. The more different genetic information is present, the better
prepared a species to deal with a range of environmental factors.
Several processes influence the genetic makeup of organisms in a species. Among
those influences is the combination of various alleles into a genotype from “parents”
that carry those alleles. Another factor determining genetic makeup is the random
mutations of one type of allele into another. These two cases are dealt with in the
model of this chapter. The following chapter will then explore the impacts of natural
selection and fitness in conjunction with mutation on genotype distribution.
To model the process of genotype mixing and mutation we restrict ourselves—
without loss of generality—to the case of two alleles A and B, which are drawn
randomly from an initial pool of 200 A alleles and 300 B alleles. The results of the
simple mating of two alleles are explained by the Hardy–Weinberg law: this law
states that the genotype frequencies are determined in a random mating process.
These genotype frequencies are for AA, p^2; for AB, 2 * p * q; for BB, q^2, where p
and q are the A and B allele frequencies, respectively. In our sample problem,
p ¼ 200/500 or 0.4 and q ¼ 300/500 or 0.6 for our initial pool of 200 A alleles and
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_12,
© Springer International Publishing Switzerland 2014
99