Biology Reference
In-Depth Information
Chapter 9
C
HANGES IN THE
D
EMOGRAPHIC
T
RENDS OF
P
INK
R
IVER
D
OLPHINS
(
I
NIA
)
AT THE
M
ICROGEOGRAPHICAL
L
EVEL IN
P
ERUVIAN AND
B
OLIVIAN
R
IVERS AND
W
ITHIN THE
U
PPER
A
MAZON
:
M
ICROSATELLITES AND
M
TDNA
A
NALYSES AND
I
NSIGHTS INTO
I
NIA
'
S
O
RIGIN
Manuel Ruiz-García
Laboratorio de Genética de Poblaciones Molecular-Biología Evolutiva. Unidad de
Genética. Departamento de Biología. Facultad de Ciencias. Pontificia Universidad
Javeriana, Bogotá DC, Colombia
A
BSTRACT
More than 200 pink river dolphins (
Inia geoffrensis
and
Inia boliviensis
) were
sampled in diverse rivers of Colombia, Peru, Brazil and Bolivia. Ten microsatellites and
400 bp of the mitochondrial control region (D-loop) gene were analyzed with special
emphasis on three Peruvian rivers (Ucayali, Marañon and Napo-Curaray) and the
Bolivian Mamoré River (and tributaries)
.
Of the
different evolutionary demographic tests
applied to the microsatellite and mtDNA data, the tests of Kimmel et al., (2008) and
Zhivotovsky et al., (2000) provided the most insights about the demographic history of
the pink river dolphin. These tests showed that initial bottlenecks occurred prior to very
recent population expansions in the diverse areas studied. Two tests (Zhivotovsky and
Garza & Williamson) revealed a very strong bottleneck in the origin of the Bolivian
population and not during its population expansion. Together, the microsatellite and
mtDNA, analyses revealed a strong population expansion for the overall upper Amazon
sample and supported that the population expansion and colonization of
Inia
throughout
the Amazon, Orinoco and Beni-Mamoré basins occurred in the last 200,000 years ago
(and in the majority of cases between 4,000-50,000 years ago) and not several millions of
years ago as was claimed by other authors. Furthermore, the original population was the
mruiz@javeriana.edu.co , mruizgar@yahoo.es.
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