An adaptive explanation for geographically structured allozyme variation in Dichroplus elongatus (Orthoptera: Acrididae)
Previous studies on allozyme variation in five populations of the grasshopper Dichroplus elongatus along a geographical gradient in Argentina revealed a significant degree of population structuring and a significant association between one of the loci (Aat-1) and latitude. As this could not be entir...
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| Autores principales: | , , |
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1997
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00221333_v76_n1_p33_Sequeira http://hdl.handle.net/20.500.12110/paper_00221333_v76_n1_p33_Sequeira |
| Aporte de: |
| Sumario: | Previous studies on allozyme variation in five populations of the grasshopper Dichroplus elongatus along a geographical gradient in Argentina revealed a significant degree of population structuring and a significant association between one of the loci (Aat-1) and latitude. As this could not be entirely explained by historical factors, the possible adaptive significance of this locus or loci in linkage disequilibrium was investigated in the present study, with an emphasis on the role of environmental variables correlated with latitude. The present paper reports a study of the geographical organization of allozyme diversity over a wider range of the distribution of D. elongatus. The relation of allelic frequencies with geographic climatic variables was analysed. We have found (i) that different loci (Aat-1 and Pep-1) covary significantly with different variables, (ii) discordance between genetic and geographical distances, (iii) copious gene flow that would mask allelic frequency differences due solely to genetic drift, (iv) and temporal stability of the gradient found. The results suggest that causes other than drift and migration may explain the observed directional patterns of variation in D. elongatus. |
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