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Contrasting views over a hybrid complex: Between speciation and evolutionary "dead-end"

Pala, Irene LU and Coelho, Maria Manuela (2005) In Gene 347(2). p.283-294
Abstract
The Squalius alburnoides complex, of hybrid origin, comprises diploid, triploid and tetraploid forms and has a widespread distribution in the Iberian waters. The southern populations of this complex, sympatric with S. pyrenaicus, show high genetic variability, diversity of forms and reproductive modes which create pathways that may allow for the establishment of a new species in the future. Here we report a contrasting view over the S. alburnoides complex: in the Mondego River basin (northern Portugal), nuclear "non-hybrid" and tetraploid forms are absent and a clearly impoverished genetic diversity is observed, contributing to a general scarcity of possibilities of generating novel genetic material. Moreover, the bisexual species involved... (More)
The Squalius alburnoides complex, of hybrid origin, comprises diploid, triploid and tetraploid forms and has a widespread distribution in the Iberian waters. The southern populations of this complex, sympatric with S. pyrenaicus, show high genetic variability, diversity of forms and reproductive modes which create pathways that may allow for the establishment of a new species in the future. Here we report a contrasting view over the S. alburnoides complex: in the Mondego River basin (northern Portugal), nuclear "non-hybrid" and tetraploid forms are absent and a clearly impoverished genetic diversity is observed, contributing to a general scarcity of possibilities of generating novel genetic material. Moreover, the bisexual species involved in the maintenance of the complex in this basin (S. carolitertii) exhibits a considerably lower genetic variability, when compared with S. pyrenaicus. The observed differences suggest that, despite being originated by similar hybridization events and maintained by analogous reproductive mechanisms, different populations of the complex were exposed to distinct evolutionary constrains, which in some cases resulted in diversification and speciation while in others led to a compromising situation in terms of evolutionary potential. Additionally, and for the first time all forms were used in the calculation of genetic distances and diversity indices, widening the possibilities of analysis of the complex by allowing the inclusion of a large part of the available data, irrespective of ploidy level. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Genetic diversity, Triploids, Cyprinids, Microsatellites, Evolutionary potential
in
Gene
volume
347
issue
2
pages
283 - 294
publisher
Elsevier
external identifiers
  • scopus:15544379137
ISSN
1879-0038
DOI
10.1016/j.gene.2004.12.010
language
English
LU publication?
no
id
c574a9f6-c72a-4a02-8682-301a6439199c (old id 1787910)
date added to LUP
2011-02-22 09:39:27
date last changed
2017-10-29 04:11:39
@article{c574a9f6-c72a-4a02-8682-301a6439199c,
  abstract     = {The Squalius alburnoides complex, of hybrid origin, comprises diploid, triploid and tetraploid forms and has a widespread distribution in the Iberian waters. The southern populations of this complex, sympatric with S. pyrenaicus, show high genetic variability, diversity of forms and reproductive modes which create pathways that may allow for the establishment of a new species in the future. Here we report a contrasting view over the S. alburnoides complex: in the Mondego River basin (northern Portugal), nuclear "non-hybrid" and tetraploid forms are absent and a clearly impoverished genetic diversity is observed, contributing to a general scarcity of possibilities of generating novel genetic material. Moreover, the bisexual species involved in the maintenance of the complex in this basin (S. carolitertii) exhibits a considerably lower genetic variability, when compared with S. pyrenaicus. The observed differences suggest that, despite being originated by similar hybridization events and maintained by analogous reproductive mechanisms, different populations of the complex were exposed to distinct evolutionary constrains, which in some cases resulted in diversification and speciation while in others led to a compromising situation in terms of evolutionary potential. Additionally, and for the first time all forms were used in the calculation of genetic distances and diversity indices, widening the possibilities of analysis of the complex by allowing the inclusion of a large part of the available data, irrespective of ploidy level.},
  author       = {Pala, Irene and Coelho, Maria Manuela},
  issn         = {1879-0038},
  keyword      = {Genetic diversity,Triploids,Cyprinids,Microsatellites,Evolutionary potential},
  language     = {eng},
  number       = {2},
  pages        = {283--294},
  publisher    = {Elsevier},
  series       = {Gene},
  title        = {Contrasting views over a hybrid complex: Between speciation and evolutionary "dead-end"},
  url          = {http://dx.doi.org/10.1016/j.gene.2004.12.010},
  volume       = {347},
  year         = {2005},
}