scholarly journals Wolbachia effects in natural populations of Chorthippus parallelus from the Pyrenean hybrid zone

2014 ◽  
Vol 27 (6) ◽  
pp. 1136-1148 ◽  
Author(s):  
M. Zabal-Aguirre ◽  
F. Arroyo ◽  
J. García-Hurtado ◽  
J. de la Torre ◽  
G. M. Hewitt ◽  
...  
Keyword(s):  
Hybrid Zone ◽  
Natural Populations ◽  
Chorthippus Parallelus

Broad-scale mapping of a hybrid zone between subspecies of Chorthippus parallelus (Orthoptera: Acrididae)

1992 ◽  
Vol 17 (4) ◽  
pp. 359-362 ◽  
Author(s):  
R. K. BUTLIN ◽  
C. FERRIS ◽  
J. GOSALVEZ ◽  
G. M. HEWITT ◽  
M. G. RITCHIE
Keyword(s):  
Hybrid Zone ◽  
Chorthippus Parallelus ◽  
Broad Scale

Chromosomal and allelic variation in Drosophila americana: selective maintenance of a chromosomal cline

Genome ◽  
2002 ◽  
Vol 45 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Bryant F McAllister
Keyword(s):  
Natural Selection ◽  
Hybrid Zone ◽  
Allelic Variation ◽  
Natural Populations ◽  
Chromosomal Evolution ◽  
Geographic Region ◽  
Hybrid Zones ◽  
Geographic Structure ◽  
Latitudinal Transect ◽  
Selective Maintenance

Geographically structured genetic variation, as represented by clines and hybrid zones, offers unique opportunities to study adaptation and speciation in natural populations. A hybrid zone has been reported between Drosophila americana americana and Drosophila americana texana, two taxa that are distinguished solely by the arrangement of their X and 4th chromosomes. In this study, samples of D. americana were collected along a latitudinal transect across the inferred hybrid zone, and the frequency of the alternative chromosomal arrangements is reported. These data illustrate that the alternative chromosomal arrangements are distributed along a shallow cline over a broad geographic region, and that the frequency of the arrangements is tightly correlated with latitude. Allelic variants at 13 RFLP loci in three genes on chromosome 4 exhibit no evidence of association with the cline. Presence of a cline for the chromosomal arrangements, as well as a general absence of geographic structure for variation at these genes, is interpreted as evidence that natural selection is responsible for the maintenance of this chromosomal cline. Furthermore, these results demonstrate that taxonomic subdivision of D. americana is unwarranted, because it exists as a cohesive species that is segregating a chromosomal fusion.Key words: chromosomal evolution, Robertsonian fusion, hybrid zone, cline, geographic variation, natural selection.

scholarly journals Meiotic imbalance in laboratory-produced hybrid males of Chorthippus parallelus parallelus and Chorthippus parallelus erythropus

1990 ◽  
Vol 56 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J. L. Bella ◽  
G. M. Hewitt ◽  
J. Gosálvez
Keyword(s):  
Hybrid Zone ◽  
Female Parent ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
X Chromosomes ◽  
F1 Hybrid ◽  
Chorthippus Parallelus ◽  
Reciprocal Differences ◽  
Rdna Expression

SummaryThe grasshopper Chorthippus parallelus has two quite distinct subspecies, which meet along the Pyrenees forming a hybrid zone. Using silver staining we show that on the French side Cp. parallelus has three nucleolar organizer regions, on the L2, L3 and X chromosomes, while on the Spanish side Cp. erythropus has only two NORs, on the L2 and L3. Laboratory F1 hybrid males show reciprocal differences in the expression of NORs. When a Cp. erythropus is female parent the male progeny show four active NORs in mitotic cells and two silver precipitates in meiotic cells, as expected. But when a Cp. parallelus female donates the X with a NOR, her male offspring have a variable disrupted nucleolar expression. Some NORs are not expressed and extra sites of cryptic rDNA are revealed. Meiosis is more disturbed in this latter F1 cross with higher levels of polyploidy, but both Fls show around 90% spermatid abnormality. Such variation in rDNA expression is also found in individuals collected from the hybrid zone, and the role of this disturbance in affecting fitness is discussed.

scholarly journals Nuclear DNA introgression across a Pyrenean hybrid zone between parapatric subspecies of the grasshopper Chorthippus parallelus

Heredity ◽  
1994 ◽  
Vol 73 (4) ◽  
pp. 436-443 ◽  
Author(s):  
Patricia Vazquez ◽  
Steven J B Cooper ◽  
Jaime Gosalvez ◽  
Godfrey M Hewitt
Keyword(s):  
Hybrid Zone ◽  
Nuclear Dna ◽  
Chorthippus Parallelus
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