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can be a rare event and, in those cases, it would be advantageous if the
evolutionary process could get started from one or a few founder individuals;
whether this is possible or not, will depend on the modification mechanisms
available to the system. And, second, because of this, the kind of mechanism
used to create genetic modification becomes of paramount importance. If
genetic modification is created by non-homogenizing operators such as point
mutation, then populations will be able to adapt and evolve. However, if
genetic variation is created by homogenizing operators such as recombina-
tion, then evolution is either altogether halted when only one founder indi-
vidual is available or seriously compromised when the number of founder
individuals is excessively small.
The importance of the initial diversity in evolution was stressed by Ernst
Mayr in what he called founder effect speciation (Mayr 1954, 1963). This
process may be thought of as the establishment of a new population due to a
founder event initiated by genetic drift and followed by natural selection. An
extreme case of a founder event is the colonization of a previously uninhab-
ited area by a single pregnant female. In nature, besides recombination, other
genetic operators are used to create modification and populations that pass
through a bottleneck are capable of adaptation, sometimes even originating
new species.
Similarly, in artificial evolutionary systems, the capability of founder
populations to evolve depends greatly on the kind of mechanism used to
create genetic modification. Indeed, if homogenizing operators are the only
source of genetic modification, populations will not be able to evolve effi-
ciently or not at all in the extreme case of only one founder individual.
In this section, we will analyze the importance of the initial diversity in
evolution in two different systems. The first evolves under mutation and has
a non-homogenizing dynamics characteristic of an efficient adaptation. The
second evolves under recombination and has a homogenizing dynamics char-
acteristic of poorly evolving systems.
12.2.1 Choosing the Population Types
In order to quantify accurately how different populations respond to the
number of actual founders in initial populations, a simple, exactly solved
problem must be chosen. This problem must allow the comparison of
dissimilarly performing genetic operators, such as the high-performing point
mutation and the less powerful recombination. In addition, the populations
