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individuals irrespective of their geographical origin were highly significant (25.5838 %, p =
0.00000 and 73.0081 %, p = 0.00000, respectively). This result ratified that rivers and
lagoons were composed of a unique pink river dolphin gene pool for the markers studied and
that there were genetic differences, especially among the individuals.
But the main population genetics results presented in this study were those obtained with
the procedures of Chesser (1991a,b) to estimate F statistics for social reproductive systems
and not demic models, as are usually applied. In the first step, some gene correlation or
coancestry parameters were estimated: = 0.595203, = 0.455277 and F = 0.569179 as well
as the current F-statistics: F
LS
= 0.25687, F
IL
= -0.06429, F
IS
= 0.20910. These values
satisfied the relationship (1 - F
IS
) = (1 - F
IL
) (1 - F
LS
). As I explained in the Materials and
Methods section, these F-statistics were assumed to reach an asymptotic value, because the
pink river dolphins at the Napo-Curaray rivers are old enough to reach this condition, and
then several simulations, with diverse constant population reproductive parameters, were
constructed to obtain possible asymptotic F-statistic values which agreed with the F-statistics
obtained from the data. Henceforth, those population parameters which generated simulated
F-statistics very similar to those directly observed throughout the real data, could be used to
decide if the pink river dolphin populations have a social reproductive system or if they
behave as demic units. Some of the different Chesser's simulations were as follows (Figure
2): The first (A) simulation had values of s = 8, n = 5, m = 1, b = 5, g = 1250 (and migration
rates, for males d
m
= 1, and for females d
f
= 0 with calculated throughout the values of n, m
and b employed in the simulation) and yielded the asymptotic F-statistic values F
LS
=
0.17426, F
IL
= -0.20221, and F
IS
= 0.00729, which did not agree with the calculated F-statistic
values (F
LS
= 0.25687, F
IL
= -0.06429, F
IS
= 0.20910). Thus, the population parameters used
in this simulation did not seem be those present in the real pink river dolphin populations that
produced the observed F-statistic values. (B) The simulation values of s = 8, n = 12, m = 4, b
= 3, g = 1250 (and migration rates, for males of d
m
= 1, and for females, d
f
= 0) yielded the
asymptotic F-statistic values F
LS
= 0.01772, F
IL
= -0.01611, and F
IS
= 0.00152, which agreed
even less with F-statistic values obtained than the previous simulation. (C) With the different
values of s = 8, n = 5, m = 4, b = 3, and g = 1250 (and the migration rates, for males d
m
= 1,
and for females d
f
= 0), the simulation provided the asymptotic F-statistic values F
LS
=
0.07308, F
IL
= -0.07089, and F
IS
= 0.00439. These did not agree with the F-statistic values
obtained, although the F
IL
value is similar to that obtained directly from the molecular data.
(D) With the values of s = 8, n = 20, m = 1, b = 20, and g = 1250 (and migration rates, for
males d
m
= 1, and for females d
f
= 0) the simulation yielded the asymptotic F-statistic values
of F
LS
= 0.16666, F
IL
= -0.19305, and F
IS
= 0.00572, which did not agree with the F-statistic
values obtained. (E) When the values were s = 8, n = 25, m = 3, b = 25, and g = 1250 (and the
migration rates, for males d
m
= 0.7, and for females d
f
= 0.3) the simulation provided the
following asymptotic F-statistic values: F
LS
= 0.15196, F
IL
= -0.16999, and F
IS
= 0.04290,
which also did not agree with the F-statistic values obtained. Nevertheless, the next
simulations showed a considerably better fit between the simulated and the real F-statistic
values. (F) The simulation values of: s = 8, n = 8, m = 2, b = 2, and g = 1250 (and the
migration rates, for males d
m
= 0.1, and for females d
f
= 0) yielded the asymptotic F-statistic
values F
LS
= 0.21821, F
IL
= -0.01182, and F
IS
= 0.20897. The F
IS
value was almost identical
to the real value obtained. The F
LS
value was relatively similar to the real one, but the excess
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