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Speciation, Divergence, and the Origin of Gryllus rubens: Behavior, Morphology, and Molecules.

Gray DA - Insects (2011)

Bottom Line: This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions.This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule.The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA. dave.gray@csun.edu.

ABSTRACT
The last 25 years or so has seen a huge resurgence of interest in speciation research. This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions. Here I review about a decade of work on the sister species of field crickets Gryllus texensis and G. rubens. This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule. The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

No MeSH data available.


Contrasting models of speciation. Figure 7a shows the classical gradualist model with divergence attributable to approximately equal changes in both sister lineages; Figure 7b shows a punctuational view of species formation, with the majority of divergence attributable to rapid change within one ‘daughter’ lineage and relatively little change within the ‘parental’ lineage. Currently available molecular data favor a peripatric ‘puctuational’ origin of G. rubens.
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f7-insects-02-00195: Contrasting models of speciation. Figure 7a shows the classical gradualist model with divergence attributable to approximately equal changes in both sister lineages; Figure 7b shows a punctuational view of species formation, with the majority of divergence attributable to rapid change within one ‘daughter’ lineage and relatively little change within the ‘parental’ lineage. Currently available molecular data favor a peripatric ‘puctuational’ origin of G. rubens.

Mentions: In short, the molecular phylogeographic work [77] altered my interpretation of speciation in these taxa from a symmetric gradualist model to an asymmetric punctuational model, with the important changes being within the proto-rubens lineage (Figure 7). Does that imply that sexual selection and the observed genetic correlation between male song and female preference in G. texensis was not important in speciation? Genetic correlations can arise via pleiotropy or linkage, and in the case of sexually selected traits/preferences assortative mating can create and maintain a genetic correlation. For example, our previous work with a different G. texensis song character, numbers of pulses per trill (PPT), showed that there is a strong genetic correlation between male PPT and female preference for PPT in the wild, but that that genetic correlation disappears after random mating in the laboratory [79]. This demonstrates that it is assortative mating in the wild that creates and maintains the observed genetic correlation between these traits in G. texensis. In contrast, an important recent study of pulse rate and pulse rate preference quantitative trait loci in the Hawaiian crickets Laupala kohalensis and L. paranigra demonstrated that the observed strong genetic correlation was due mostly to either close physical linkage or pleiotropy [80]. The genetic basis of the G. texensis pulse rate/preference genetic correlation is unknown, and the corresponding genetic correlation has not been investigated in G. rubens. However, the phylogeographic data polarize the ancestral state of proto-rubens and suggest that that ancestor was, in effect, the G. texensis lineage that has led to the current G. texensis. As G. texensis of today show a strong pulse rate/preference genetic correlation, that shared ancestor likely did also, and so—in the absence of any supporting data whatsoever—it is reasonable to think that a similar genetic correlation may have been important in proto-rubens song/preference evolution.


Speciation, Divergence, and the Origin of Gryllus rubens: Behavior, Morphology, and Molecules.

Gray DA - Insects (2011)

Contrasting models of speciation. Figure 7a shows the classical gradualist model with divergence attributable to approximately equal changes in both sister lineages; Figure 7b shows a punctuational view of species formation, with the majority of divergence attributable to rapid change within one ‘daughter’ lineage and relatively little change within the ‘parental’ lineage. Currently available molecular data favor a peripatric ‘puctuational’ origin of G. rubens.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553458&req=5

f7-insects-02-00195: Contrasting models of speciation. Figure 7a shows the classical gradualist model with divergence attributable to approximately equal changes in both sister lineages; Figure 7b shows a punctuational view of species formation, with the majority of divergence attributable to rapid change within one ‘daughter’ lineage and relatively little change within the ‘parental’ lineage. Currently available molecular data favor a peripatric ‘puctuational’ origin of G. rubens.
Mentions: In short, the molecular phylogeographic work [77] altered my interpretation of speciation in these taxa from a symmetric gradualist model to an asymmetric punctuational model, with the important changes being within the proto-rubens lineage (Figure 7). Does that imply that sexual selection and the observed genetic correlation between male song and female preference in G. texensis was not important in speciation? Genetic correlations can arise via pleiotropy or linkage, and in the case of sexually selected traits/preferences assortative mating can create and maintain a genetic correlation. For example, our previous work with a different G. texensis song character, numbers of pulses per trill (PPT), showed that there is a strong genetic correlation between male PPT and female preference for PPT in the wild, but that that genetic correlation disappears after random mating in the laboratory [79]. This demonstrates that it is assortative mating in the wild that creates and maintains the observed genetic correlation between these traits in G. texensis. In contrast, an important recent study of pulse rate and pulse rate preference quantitative trait loci in the Hawaiian crickets Laupala kohalensis and L. paranigra demonstrated that the observed strong genetic correlation was due mostly to either close physical linkage or pleiotropy [80]. The genetic basis of the G. texensis pulse rate/preference genetic correlation is unknown, and the corresponding genetic correlation has not been investigated in G. rubens. However, the phylogeographic data polarize the ancestral state of proto-rubens and suggest that that ancestor was, in effect, the G. texensis lineage that has led to the current G. texensis. As G. texensis of today show a strong pulse rate/preference genetic correlation, that shared ancestor likely did also, and so—in the absence of any supporting data whatsoever—it is reasonable to think that a similar genetic correlation may have been important in proto-rubens song/preference evolution.

Bottom Line: This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions.This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule.The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA. dave.gray@csun.edu.

ABSTRACT
The last 25 years or so has seen a huge resurgence of interest in speciation research. This has coincided with the development and widespread use of new tools in molecular genetics, especially DNA sequencing, to inform ecological and evolutionary questions. Here I review about a decade of work on the sister species of field crickets Gryllus texensis and G. rubens. This work has included analysis of morphology, behavior, and the mitochondrial DNA molecule. The molecular work in particular has dramatically re-shaped my interpretation of the speciational history of these taxa, suggesting that rather than 'sister' species we should consider these taxa as 'mother-daughter' species with G. rubens derived from within a subset of ancestral G. texensis.

No MeSH data available.