Biology Reference
In-Depth Information
Alternative geometric positioning of the founders can make other types
of differences. For example, in
Fig. 14.3,
populations n and o have founders
in two lines with males and females juxtaposed. Trials were also conducted
where the founders were in two lines, but each line was unisexual, being
either all male or all female. There were only very slight differences in
population growth rates, observed heterozygosity, and F values from those
depicted in Fig. 14.3 (data not shown). Figure 14.4 indicates that the greatest
unique allele retention is achieved when the founders are placed in two
unisexual lines and maximum dispersal is 20 grid units (population O). This
represents an approximately 7.5% increase over a population with founders
in a square and maximum dispersal of 10 grid units (population g).
Similarly, differences in diversity retention occurred when founders
were in lines and either had 4 grid units between them or not
(
Fig. 14.5)
.
As
shown previously, increased dispersal of dispersules, at least up to a point,
can increase population growth rate (graph A, populations O and Q have
maximum dispersal of 20 grid units, while n and p have a maximum of 10
units). Also as shown previously, increased spacing between founders can
increase population growth (Q and p have 4 grid units between founders,
1000
g
l
N
O
900
800
N
O
l
g
N
O
l
700
g
O
N
l
O
l
O
N
O
g
O
l
O
O
O
O
O
O
O
l
N
l
l
l
l
l
l
l
l
N
g
N
N
N
g
N
N
N
N
N
g
g
g
g
g
g
g
g
g
600
0
5
10
15
GENERATION
Fig. 14.4
Unique alleles retained in populations that differ in the placement of founders, and
in offspring and microgamete dispersal distances. Input conditions for populations g and l
have been described in
Fig. 14.3
and the text. In brief, for both, the 20 founders are placed in
squares with no grid points between alternating male and female founders, and maximum
dispersal of offspring and pollen is 10 grid points for g and 20 grid points for l. Populations
N and O have identical input conditions except that founders were placed in two lines, one
comprising only males, the other only females. There were no grid points between adjacent
founders. Maximum offspring and microgamete dispersal distances are 10 grid points for
population N and 20 points for O.
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