You are in the accessibility menu

Please use this identifier to cite or link to this item: http://acervodigital.unesp.br/handle/11449/68259
Title: 
Strong selection against hybrids at a hybrid zone in the Ensatina ring species complex and its evolutionary implications
Author(s): 
Institution: 
  • University of California, Berkeley
  • Lawrence Berkeley National Laboratory
  • Universidade Estadual Paulista (UNESP)
  • Centre de Biologie et de Gestion des Populations (CBGP/INRA)
ISSN: 
0014-3820
Abstract: 
The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders E. eschscholtzii xanthoptica and E. eschscholtzii platensis hybridize in the central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was resampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (1) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730 m to 2000 m; (2) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over five generations; (3) there were very few if any putative F1s, but a relatively high number of backcrossed individuals in the central portion of transects: and (4) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit showed maximum values near the center of the zones. Using estimates of cline width and dispersal, we infer strong selection against hybrids. This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent selection and reinforces the value of Ensatina as a system for the study of divergence and speciation at multiple stages. © 2005 The Society for the Study of Evolution. All rights reserved.
Issue Date: 
1-Jun-2005
Citation: 
Evolution, v. 59, n. 6, p. 1334-1347, 2005.
Time Duration: 
1334-1347
Keywords: 
  • Concordant clines
  • Ensatina eschscholtzii
  • Hybrid zones
  • Linkage disequilibrium
  • Maximum likelihood
  • Ring species
  • Selection against hybrids
  • Speciation
  • cytochrome b
  • isoenzyme
  • evolution
  • hybrid zone
  • selection
  • speciation (biology)
  • Amphibia
  • animal
  • comparative study
  • gene linkage disequilibrium
  • genetic selection
  • genetics
  • geography
  • heterozygote detection
  • hybridization
  • longitudinal study
  • physiology
  • pigmentation
  • population genetics
  • restriction fragment length polymorphism
  • species difference
  • statistical model
  • United States
  • Animals
  • California
  • Cytochromes b
  • Evolution
  • Genetics, Population
  • Geography
  • Heterozygote Detection
  • Hybridization, Genetic
  • Isoenzymes
  • Likelihood Functions
  • Linkage Disequilibrium
  • Longitudinal Studies
  • Pigmentation
  • Polymorphism, Restriction Fragment Length
  • Selection (Genetics)
  • Species Specificity
  • Urodela
  • North America
  • Western Hemisphere
  • World
  • Amphiuma means
  • Caudata
  • Ensatina
  • Ensatina eschscholtzii platensis
  • Ensatina eschscholtzii xanthoptica
  • Plethodontidae
Source: 
http://ib.berkeley.edu/labs/wake/2005_Evolution_Ensatina.pdf
URI: 
Access Rights: 
Acesso aberto
Type: 
outro
Source:
http://repositorio.unesp.br/handle/11449/68259
Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

There are no files associated with this item.
 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.