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<DIV id=productTitle><STRONG></STRONG> </DIV>
<DIV><STRONG>Biological Journal of the Linnean Society</STRONG></DIV>
<DIV class=articleDetails><A
href="http://onlinelibrary.wiley.com/doi/10.1111/bij.2011.102.issue-4/issuetoc"
shape=rect><FONT color=#000000><SPAN id=volumeNumber>Volume 102</SPAN>, <SPAN
id=issueNumber>Issue 4</SPAN>, </FONT></A><SPAN id=issuePages>pages
812–827</SPAN>, <SPAN id=issueDate>April 2011</SPAN></DIV>
<DIV class=articleTitle><SPAN>Article first published online: 14 MAR 2011</DIV>
<DIV id=doi>DOI: 10.1111/j.1095-8312.2011.01616.x</DIV>
<DIV class=articleTitle></SPAN> </DIV>
<DIV class=articleTitle><FONT size=4>The Amazon River system as an ecological
barrier driving genetic differentiation of the pink dolphin (<EM>Inia
geoffrensis</EM>)</FONT></DIV>
<DIV class="citation articleInformationHeader"
xmlns="http://www.w3.org/1999/xhtml">
<DIV id=cr1>CLAUDIA HOLLATZ<SUP>1</SUP>, SIBELLE TORRES VILA<IMG
src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/0000c7.gif">A<SUP>1,2</SUP>,
RODRIGO A. F. REDONDO<SUP>1</SUP>, MÍRIAM MARMONTEL<SUP>3</SUP>, C. SCOTT
BAKER<SUP>4</SUP>, FABRÍCIO R. SANTOS<SUP>1,*</SUP></DIV>
<P id=publishedOnlineDate><SUP>1</SUP> Laboratório de Biodiversidade e Evolução
Molecular, Departamento de Biologia Geral, ICB, Universidade Federal de Minas
Gerais, Belo Horizonte, MG, Brazil, 31270-010<SUP>2</SUP> Dipartimento di
Biologia ed Evoluzione, Università di Ferrara, 4100 Ferrara, Italy<SUP>3</SUP>
Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, AM, Brazil,
69470-000<SUP>4</SUP> Department of Fisheries and Wildlife, Marine Mammal
Institute, Oregon State University, Newport, Oregon, 97361, USA. Correspondence:
FABRÍCIO R. SANTOS, E-mail: <!--TODO: clickthrough URL--><A
title="Link to email address" href="mailto:fsantos@icb.ufmg.br" shape=rect><FONT
color=#007e8a>fsantos@icb.ufmg.br</FONT></A></P>
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<UL class="" id=footnotes><FONT color=#007e8a></FONT></UL>
<UL class="" id=footnotes><FONT color=#007e8a></FONT></UL>
<DIV id=publicationHistoryDetails jQuery1300138259568="10">
<H4>Summary</H4></DIV></DIV></DIV></DIV>
<DIV id=productContent>
<DIV id=fulltext xmlns="http://www.w3.org/1999/xhtml">
<DIV id=abstract>
<DIV class=para>
<P>The pink dolphin (<EM>Inia geoffrensis</EM>) is widely distributed along the
Amazon and Orinoco basins, covering an area of approximately 7 million
km<SUP><FONT size=1>2</FONT></SUP>. Previous morphological and genetic studies
have proposed the existence of at least two evolutionary significant units: one
distributed across the Orinoco and Amazon basins and another confined to the
Bolivian Amazon. The presence of barriers in the riverine environment has been
suggested to play a significant role in shaping present-day patterns of
ecological and genetic structure for this species. In the present study, we
examined the phylogeographic structure, lineage divergence time and historical
demography using mitochondrial (mt)DNA sequences in different pink dolphin
populations distributed in large and small spatial scales, including two
neighbouring Brazilian Amazon populations. mtDNA control region (CR) analysis
revealed that the Brazilian haplotypes occupy an intermediate position compared
to three previously studied geographic locations: the Colombian Amazon, the
Colombian Orinoco, and the Bolivian Amazon. On a local scale, we have identified
a pattern of maternal isolation between two neighbouring populations from
Brazil. Six mtDNA CR haplotypes were identified in Brazil with no sharing
between the two populations, as well as specific cytochrome <EM>b</EM> (cyt
<EM>b</EM>) haplotypes identified in each locality. In addition, we analyzed
autosomal microsatellites to investigate male-mediated gene flow and demographic
changes within the study area in Brazil. Data analysis of 14 microsatellite loci
failed to detect significant population subdivision, suggesting that
male-mediated gene flow may maintain homogeneity between these two locations.
Moreover, both mtDNA and microsatellite data indicate a major demographic
collapse within Brazil in the late Pleistocene. Bayesian skyline plots (BSP) of
mtDNA data revealed a stable population for Colombian and Brazilian Amazon
lineages through time, whereas a population decline was demonstrated in the
Colombian Orinoco lineage. Moreover, BSP and Tajima's <EM>D</EM> and Fu's
<EM>F</EM><SUB><FONT size=1>s</FONT></SUB> tests revealed a recent population
expansion exclusively in the Bolivian sample. Finally, we estimated that the
diversification of the <EM>Inia</EM> sp. lineage began in the Late Pliocene
(approximately 3.1 Mya) and continued throughout the Pleistocene. This
article is a US Government work and is in the public domain in the USA.
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