Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)

C. aquaticum (Acrididae: Leptysminae) inhabits water-hyacinths in the Neotropical region. The blue-flowered water-hyacinth, Eichhornia crassipes, has been introduced elsewhere without its natural enemies and has become a weed; recently C. aquaticum was considered as a possible biological control age...

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Autor principal: Colombo, Pablo Cesar
Publicado: 2008
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12105759_v105_n1_p59_Colombo
http://hdl.handle.net/20.500.12110/paper_12105759_v105_n1_p59_Colombo
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spelling paper:paper_12105759_v105_n1_p59_Colombo2023-06-08T16:10:02Z Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae) Colombo, Pablo Cesar Acrididae Chromosomal cline Cornops aquaticum Recombination Robertsonian translocations chromosome grasshopper polymorphism recombination sex determination Parana River South America Acrididae Cornops aquaticum Eichhornia Eichhornia crassipes Leptysminae Orthoptera Robertsonia C. aquaticum (Acrididae: Leptysminae) inhabits water-hyacinths in the Neotropical region. The blue-flowered water-hyacinth, Eichhornia crassipes, has been introduced elsewhere without its natural enemies and has become a weed; recently C. aquaticum was considered as a possible biological control agent. In this work, six populations were sampled and cytologically studied. C. aquaticum has 2n - 23 chromosomes in males and 24 in females, with an XO/XX sex determination system. All chromosomes are acro-telocentric and the basic karyotype includes three Robertsonian (Rb) translocations between pairs 1/6, 2/5, and 3/4. These polymorphisms are restricted to the lower course of the Paraná river, between Rosario and Buenos Aires. Fusion frequencies increase southwards, thus showing a geographical cline. The polymorphisms mostly accord with Hardy-Weinberg and gametic phase equilibria. The rearrangements cause a drastic chiasma repatterning in the fusion bivalents (or trivalents) which reduces the proximal Asma frequency. Recombination is also reduced due to the loss of independent segregation. A recombination index that takes into account both these factors correlates negatively with the her of pairs of chromosomes affected by fusions among populations, which does not accord with the "central-marginal" pattern. Fil:Colombo, P.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2008 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12105759_v105_n1_p59_Colombo http://hdl.handle.net/20.500.12110/paper_12105759_v105_n1_p59_Colombo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Acrididae
Chromosomal cline
Cornops aquaticum
Recombination
Robertsonian translocations
chromosome
grasshopper
polymorphism
recombination
sex determination
Parana River
South America
Acrididae
Cornops aquaticum
Eichhornia
Eichhornia crassipes
Leptysminae
Orthoptera
Robertsonia
spellingShingle Acrididae
Chromosomal cline
Cornops aquaticum
Recombination
Robertsonian translocations
chromosome
grasshopper
polymorphism
recombination
sex determination
Parana River
South America
Acrididae
Cornops aquaticum
Eichhornia
Eichhornia crassipes
Leptysminae
Orthoptera
Robertsonia
Colombo, Pablo Cesar
Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
topic_facet Acrididae
Chromosomal cline
Cornops aquaticum
Recombination
Robertsonian translocations
chromosome
grasshopper
polymorphism
recombination
sex determination
Parana River
South America
Acrididae
Cornops aquaticum
Eichhornia
Eichhornia crassipes
Leptysminae
Orthoptera
Robertsonia
description C. aquaticum (Acrididae: Leptysminae) inhabits water-hyacinths in the Neotropical region. The blue-flowered water-hyacinth, Eichhornia crassipes, has been introduced elsewhere without its natural enemies and has become a weed; recently C. aquaticum was considered as a possible biological control agent. In this work, six populations were sampled and cytologically studied. C. aquaticum has 2n - 23 chromosomes in males and 24 in females, with an XO/XX sex determination system. All chromosomes are acro-telocentric and the basic karyotype includes three Robertsonian (Rb) translocations between pairs 1/6, 2/5, and 3/4. These polymorphisms are restricted to the lower course of the Paraná river, between Rosario and Buenos Aires. Fusion frequencies increase southwards, thus showing a geographical cline. The polymorphisms mostly accord with Hardy-Weinberg and gametic phase equilibria. The rearrangements cause a drastic chiasma repatterning in the fusion bivalents (or trivalents) which reduces the proximal Asma frequency. Recombination is also reduced due to the loss of independent segregation. A recombination index that takes into account both these factors correlates negatively with the her of pairs of chromosomes affected by fusions among populations, which does not accord with the "central-marginal" pattern.
author Colombo, Pablo Cesar
author_facet Colombo, Pablo Cesar
author_sort Colombo, Pablo Cesar
title Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
title_short Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
title_full Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
title_fullStr Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
title_full_unstemmed Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)
title_sort cytogeography of three parallel robertsonian polymorphisms in the water-hyacinth grasshopper, cornops aquaticum (orthoptera: acrididae)
publishDate 2008
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_12105759_v105_n1_p59_Colombo
http://hdl.handle.net/20.500.12110/paper_12105759_v105_n1_p59_Colombo
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