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Differential high-altitude adaptation and restricted gene flow across a mid-elevation hybrid zone in Andean tit-tyrant flycatchers.
DuBay, Shane G; Witt, Christopher C.
Afiliação
  • DuBay SG; Department of Biology, Museum of Southwestern Biology, University of New Mexico, 167 Castetter Hall MSC03 2020, 1 University of New Mexico, Albuquerque, NM, 87131, USA.
Mol Ecol ; 23(14): 3551-65, 2014 Jul.
Article em En | MEDLINE | ID: mdl-24943893
The tropical Andes are a global hotspot of avian diversity that is characterized by dramatic elevational shifts in community composition and a preponderance of recently evolved species. Bird habitats in the Andes span a nearly twofold range of atmospheric pressure that poses challenges for respiration, thermoregulation, water balance and powered flight, but the extent to which physiological constraints limit species' elevational distributions is poorly understood. We report a previously unknown hybrid zone between recently diverged flycatchers (Aves, Tyrannidae) with partially overlapping elevational ranges. The southern Anairetes reguloides has a broad elevational range (0-4200 m), while the northern Anairetes nigrocristatus is restricted to high elevations (>2200 m). We found hybrids in central Peru at elevations between ~3100 and 3800 m, with A. nigrocristatus above this elevation and A. reguloides below. We analysed variation in haematology, heart mass, morphometrics, plumage and one mitochondrial and three nuclear loci across an elevational transect that encompasses the hybrid zone. Phenotypic traits and genetic markers all showed steep clines across the hybrid zone. Haemoglobin concentration, haematocrit, mean cellular haemoglobin concentration and relative heart mass each increased at altitude more strongly in A. reguloides than in A. nigrocristatus. These findings suggest that A. nigrocristatus is more resistant than A. reguloides to high-altitude hypoxic respiratory stress. Considering that the ancestor of the genus is suggested to have been restricted to high elevations, A. reguloides may be secondarily adapted to low altitude. We conclude that differential respiratory specialization on atmospheric pressure combined with competitive exclusion maintains replacement along an elevational contour, despite interbreeding.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Adaptação Fisiológica / Aves Canoras / Fluxo Gênico / Altitude / Genética Populacional Limite: Animals País/Região como assunto: America do sul / Peru Idioma: En Revista: Mol Ecol Assunto da revista: BIOLOGIA MOLECULAR / SAUDE AMBIENTAL Ano de publicação: 2014 Tipo de documento: Article País de afiliação: Estados Unidos País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Adaptação Fisiológica / Aves Canoras / Fluxo Gênico / Altitude / Genética Populacional Limite: Animals País/Região como assunto: America do sul / Peru Idioma: En Revista: Mol Ecol Assunto da revista: BIOLOGIA MOLECULAR / SAUDE AMBIENTAL Ano de publicação: 2014 Tipo de documento: Article País de afiliação: Estados Unidos País de publicação: Reino Unido