Biology Reference
In-Depth Information
0.08
0.08
o
o
o
o
o
o
o
o
o
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o
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o
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oo
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oo
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B
A
mm
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m
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m
m
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m
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m
m
m
m
m
m
m
m
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m
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m
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m
m
m
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m
m
m
m
m
mm
m
m
m
m
m
m
mm
m
mm
mmm
m
m
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0.06
0.06
nn
nn
n
nn
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nn
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nn
n
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n
n
n
n
n
n
n
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n
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nnnnn
n
p
pp
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p
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p
p
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p
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p
p
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p
p
p
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p
p
p
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p
pp
pp
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p
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p
pp
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p
0.04
0.04
OO
OO
O
OO
OO
O
OO
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M
MM
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MM
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M
M
M
M
M
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M
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M
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MMM
NN
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N
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0.02
0.02
P
PP
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P
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PPP
P
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P
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o
o
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-0.02
-0.02
0
10
20
30
40
50
60
70
0
10
20
30
40
50
60
70
GENERATION
GENERATION
Fig. 15.3
Values of F across generations for trials modeling establishment of the dioecious
shrub
Lindera benzoin
. 172 founders were placed either in squares of 43 at each corner with no
founder closer than 80 grid units from a border (A, lowercase letters), or in a single central
square in the preserve (B, uppercase letters). In every trial, there were 4 grid points between
all adjacent founders. The different trials are compared to basic trials M or m, in which 25% of
offspring are dispersed to, and 25% of pollen comes from, each of the four dispersal distance
frames (see
Table 15.1)
.
Comparative trials differ as follows:
In trials N and n, more offspring are dispersed more closely to the maternal plant; 25% pollen
from each frame.
In trials O and o, 25% of an individual's offspring are dispersed to each frame; more pollen
comes from nearer the maternal plant.
In trials P and p, 25% of an individual's offspring are dispersed to each frame; more pollen
comes from a greater distance from the maternal plant.
For complete details on the trials, see text and Table 15.1.
Under the given circumstances, changes in heterozygosity and F seem
to be more sensitive to changes in pollen dispersal distances than offspring
dispersal distances. If one is restoring a species in which inbreeding is
problematic, then planting individuals in a central square and promoting
long-distance pollen dispersal (trial P) would be the best choice. However,
this effect will likely be transient (see earlier examples on subdivision) and
the relative differences in F will decrease as the subpopulations increasingly
merge.
Loss of unique alleles over generations in these virtual spicebush
population trials is depicted in
Fig. 15.4
.
In contrast to heterozygosity and
F values, loss of unique alleles is only slightly altered if founders are placed
in different geometric positions (Fig. 15.4, graph A versus graph B) or if
offspring or pollen dispersal distances differ. The greatest differences occur
between trial o and trial P, suggesting that 4% more unique alleles will be
conserved on average if founders are in one contiguous square with more
pollen coming from a greater distance (trial P) relative to having founders
in four distinct corner squares with more pollen coming from nearer to
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