Biology Reference
In-Depth Information
If the above is true, then by moving the founders to the right along
the lower border (panel C) in successive increments, one should see F
increase with greater distance from the left border since the noted factors
should become increasingly influential. To test whether this was the
case, three trials were conducted in which everything was held constant
beginning with the initial conditions described above (starting with the
basic input fi le, labeled with a “2”), but in successive trials, the two lines
of 10 founders initially placed in the lower left corner of the preserve were
moved increasing distances to the right, but not up. Figure 8.10 depicts the
change in F across generations as the founders are placed at horizontally
increasing distances from the left border. As predicted, F (inbreeding)
increases as the founders increase in distance to the right from the corner
because of the factors noted above. In interpreting these results, one concern
was the infl uence of population size. As shown in
Fig. 8.3,
under the given
conditions, populations grow at faster rates when the founders are placed
at increasing distances from the borders, and this is also the case here
when they are moved away from one border to the right (data not shown).
Are differences in F mainly due to differences in population size (smaller
populations force more changes induced by inbreeding and/or drift in
allele frequencies)?
0.07
F
F
F
F
FF
T
F
F
T
T
F
T
T
2
T
T
F
T
F
22
2
2
2
F
TT
2
2
2
0.03
TT
2
F
F
2
TT
2
F
2
T
2
2
T
F
2
-0.01
T
F
2
F
F
T
2
2
T
T
T
F
2
F
2
-0.05
0
7
14
21
GENERATION
Fig. 8.10
Change in mean F values (30 replicate runs per trial) for trials in which founders are
placed at increasing distances to the right, but not up, from the left border of a preserve. Trial
2 = founders in two horizontal lines of 10 each starting from lower left corner (the basic input
fi le); trial T = founders moved 10 grid units to the right; trial F = founders moved 50 units right.
All trials were signifi cantly different (
t
tests of means p values are > 0.05) at generation 20.
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