Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns

Autores
Martí, D.A.; Bidau, C.J.
Año de publicación
2001
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Dichroplus pratensis has a complex system of Robertsonian rearrangements with central-marginal distribution; marginal populations are standard telocentric. Standard bivalents show a proximal-distal chiasma pattern in both sexes. In Robertsonian individuals a redistribution of chiasmata occurs: proximal chiasmata are suppressed in fusion trivalents and bivalents which usually display a single distal chiasma per chromosome arm. In this paper we studied the synaptic patterns of homologous chromosomes at prophase I of different Robertsonian status in order to find a mechanistic explanation for the observed phenomenon of redistribution of chiasmata. Synaptonemal complexes of males with different karyotypes were analysed by transmission electron microscopy in surface-spread preparations. The study of zygotene and early pachytene nuclei revealed that in the former, pericentromeric regions are the last to synapse in Robertsonian trivalents and bivalents and normally remain asynaptic at pachytene in the case of trivalents, but complete pairing in bivalents. Telocentric (standard) bivalents usually show complete synapsis at pachytene, but different degrees of interstitial asynapsis during zygotene, suggesting that synapsis starts in opposite (centromeric and distal) ends. The sequential nature of synapsis in the three types of configuration is directly related to their patterns of chiasma localisation at diplotene-metaphase I, and strongly supports our previous idea that Rb fusions instantly produce a redistribution of chiasmata towards chromosome ends by reducing the early pairing regions (which pair first, remain paired longer and thus would have a higher probability of forming chiasmata) from four to two (independently of the heterozygous or homozygous status of the fusion). Pericentrometric regions would pair the last, thus chiasma formation is strongly reduced in these areas contrary to what occurs in telocentric bivalents.
Fil:Bidau, C.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fuente
Hereditas 2001;134(3):245-254
Materia
animal experiment
animal tissue
article
chromosomal localization
chromosome arm
chromosome bivalent
chromosome chiasm
chromosome pairing
gene fusion
grasshopper
heterozygote
homozygote
karyotype
male
metaphase
nonhuman
pachytene
prophase
Robertsonian chromosome translocation
transmission electron microscopy
Animals
Chromosome Pairing
Chromosomes
Crossing Over, Genetic
Grasshoppers
Heterozygote
Homozygote
Karyotyping
Male
Meiosis
Metaphase
Testis
Acrididae
Animalia
Dichroplus
Invertebrata
Melanoplinae
Robertsonia
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/2.5/ar
Repositorio
Biblioteca Digital (UBA-FCEN)
Institución
Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
OAI Identificador
paperaa:paper_00180661_v134_n3_p245_Marti

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oai_identifier_str paperaa:paper_00180661_v134_n3_p245_Marti
network_acronym_str BDUBAFCEN
repository_id_str 1896
network_name_str Biblioteca Digital (UBA-FCEN)
spelling Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patternsMartí, D.A.Bidau, C.J.animal experimentanimal tissuearticlechromosomal localizationchromosome armchromosome bivalentchromosome chiasmchromosome pairinggene fusiongrasshopperheterozygotehomozygotekaryotypemalemetaphasenonhumanpachyteneprophaseRobertsonian chromosome translocationtransmission electron microscopyAnimalsChromosome PairingChromosomesCrossing Over, GeneticGrasshoppersHeterozygoteHomozygoteKaryotypingMaleMeiosisMetaphaseTestisAcrididaeAnimaliaDichroplusInvertebrataMelanoplinaeRobertsoniaDichroplus pratensis has a complex system of Robertsonian rearrangements with central-marginal distribution; marginal populations are standard telocentric. Standard bivalents show a proximal-distal chiasma pattern in both sexes. In Robertsonian individuals a redistribution of chiasmata occurs: proximal chiasmata are suppressed in fusion trivalents and bivalents which usually display a single distal chiasma per chromosome arm. In this paper we studied the synaptic patterns of homologous chromosomes at prophase I of different Robertsonian status in order to find a mechanistic explanation for the observed phenomenon of redistribution of chiasmata. Synaptonemal complexes of males with different karyotypes were analysed by transmission electron microscopy in surface-spread preparations. The study of zygotene and early pachytene nuclei revealed that in the former, pericentromeric regions are the last to synapse in Robertsonian trivalents and bivalents and normally remain asynaptic at pachytene in the case of trivalents, but complete pairing in bivalents. Telocentric (standard) bivalents usually show complete synapsis at pachytene, but different degrees of interstitial asynapsis during zygotene, suggesting that synapsis starts in opposite (centromeric and distal) ends. The sequential nature of synapsis in the three types of configuration is directly related to their patterns of chiasma localisation at diplotene-metaphase I, and strongly supports our previous idea that Rb fusions instantly produce a redistribution of chiasmata towards chromosome ends by reducing the early pairing regions (which pair first, remain paired longer and thus would have a higher probability of forming chiasmata) from four to two (independently of the heterozygous or homozygous status of the fusion). Pericentrometric regions would pair the last, thus chiasma formation is strongly reduced in these areas contrary to what occurs in telocentric bivalents.Fil:Bidau, C.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.2001info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://hdl.handle.net/20.500.12110/paper_00180661_v134_n3_p245_MartiHereditas 2001;134(3):245-254reponame:Biblioteca Digital (UBA-FCEN)instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesinstacron:UBA-FCENenginfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/2.5/ar2025-09-29T13:42:57Zpaperaa:paper_00180661_v134_n3_p245_MartiInstitucionalhttps://digital.bl.fcen.uba.ar/Universidad públicaNo correspondehttps://digital.bl.fcen.uba.ar/cgi-bin/oaiserver.cgiana@bl.fcen.uba.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:18962025-09-29 13:42:58.724Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturalesfalse
dc.title.none.fl_str_mv Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
title Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
spellingShingle Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
Martí, D.A.
animal experiment
animal tissue
article
chromosomal localization
chromosome arm
chromosome bivalent
chromosome chiasm
chromosome pairing
gene fusion
grasshopper
heterozygote
homozygote
karyotype
male
metaphase
nonhuman
pachytene
prophase
Robertsonian chromosome translocation
transmission electron microscopy
Animals
Chromosome Pairing
Chromosomes
Crossing Over, Genetic
Grasshoppers
Heterozygote
Homozygote
Karyotyping
Male
Meiosis
Metaphase
Testis
Acrididae
Animalia
Dichroplus
Invertebrata
Melanoplinae
Robertsonia
title_short Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
title_full Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
title_fullStr Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
title_full_unstemmed Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
title_sort Synapsis in Robertsonian heterozygotes and homozygotes of Dichroplus pratensis (Melanoplinae, Acrididae) and its relationship with chiasma patterns
dc.creator.none.fl_str_mv Martí, D.A.
Bidau, C.J.
author Martí, D.A.
author_facet Martí, D.A.
Bidau, C.J.
author_role author
author2 Bidau, C.J.
author2_role author
dc.subject.none.fl_str_mv animal experiment
animal tissue
article
chromosomal localization
chromosome arm
chromosome bivalent
chromosome chiasm
chromosome pairing
gene fusion
grasshopper
heterozygote
homozygote
karyotype
male
metaphase
nonhuman
pachytene
prophase
Robertsonian chromosome translocation
transmission electron microscopy
Animals
Chromosome Pairing
Chromosomes
Crossing Over, Genetic
Grasshoppers
Heterozygote
Homozygote
Karyotyping
Male
Meiosis
Metaphase
Testis
Acrididae
Animalia
Dichroplus
Invertebrata
Melanoplinae
Robertsonia
topic animal experiment
animal tissue
article
chromosomal localization
chromosome arm
chromosome bivalent
chromosome chiasm
chromosome pairing
gene fusion
grasshopper
heterozygote
homozygote
karyotype
male
metaphase
nonhuman
pachytene
prophase
Robertsonian chromosome translocation
transmission electron microscopy
Animals
Chromosome Pairing
Chromosomes
Crossing Over, Genetic
Grasshoppers
Heterozygote
Homozygote
Karyotyping
Male
Meiosis
Metaphase
Testis
Acrididae
Animalia
Dichroplus
Invertebrata
Melanoplinae
Robertsonia
dc.description.none.fl_txt_mv Dichroplus pratensis has a complex system of Robertsonian rearrangements with central-marginal distribution; marginal populations are standard telocentric. Standard bivalents show a proximal-distal chiasma pattern in both sexes. In Robertsonian individuals a redistribution of chiasmata occurs: proximal chiasmata are suppressed in fusion trivalents and bivalents which usually display a single distal chiasma per chromosome arm. In this paper we studied the synaptic patterns of homologous chromosomes at prophase I of different Robertsonian status in order to find a mechanistic explanation for the observed phenomenon of redistribution of chiasmata. Synaptonemal complexes of males with different karyotypes were analysed by transmission electron microscopy in surface-spread preparations. The study of zygotene and early pachytene nuclei revealed that in the former, pericentromeric regions are the last to synapse in Robertsonian trivalents and bivalents and normally remain asynaptic at pachytene in the case of trivalents, but complete pairing in bivalents. Telocentric (standard) bivalents usually show complete synapsis at pachytene, but different degrees of interstitial asynapsis during zygotene, suggesting that synapsis starts in opposite (centromeric and distal) ends. The sequential nature of synapsis in the three types of configuration is directly related to their patterns of chiasma localisation at diplotene-metaphase I, and strongly supports our previous idea that Rb fusions instantly produce a redistribution of chiasmata towards chromosome ends by reducing the early pairing regions (which pair first, remain paired longer and thus would have a higher probability of forming chiasmata) from four to two (independently of the heterozygous or homozygous status of the fusion). Pericentrometric regions would pair the last, thus chiasma formation is strongly reduced in these areas contrary to what occurs in telocentric bivalents.
Fil:Bidau, C.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
description Dichroplus pratensis has a complex system of Robertsonian rearrangements with central-marginal distribution; marginal populations are standard telocentric. Standard bivalents show a proximal-distal chiasma pattern in both sexes. In Robertsonian individuals a redistribution of chiasmata occurs: proximal chiasmata are suppressed in fusion trivalents and bivalents which usually display a single distal chiasma per chromosome arm. In this paper we studied the synaptic patterns of homologous chromosomes at prophase I of different Robertsonian status in order to find a mechanistic explanation for the observed phenomenon of redistribution of chiasmata. Synaptonemal complexes of males with different karyotypes were analysed by transmission electron microscopy in surface-spread preparations. The study of zygotene and early pachytene nuclei revealed that in the former, pericentromeric regions are the last to synapse in Robertsonian trivalents and bivalents and normally remain asynaptic at pachytene in the case of trivalents, but complete pairing in bivalents. Telocentric (standard) bivalents usually show complete synapsis at pachytene, but different degrees of interstitial asynapsis during zygotene, suggesting that synapsis starts in opposite (centromeric and distal) ends. The sequential nature of synapsis in the three types of configuration is directly related to their patterns of chiasma localisation at diplotene-metaphase I, and strongly supports our previous idea that Rb fusions instantly produce a redistribution of chiasmata towards chromosome ends by reducing the early pairing regions (which pair first, remain paired longer and thus would have a higher probability of forming chiasmata) from four to two (independently of the heterozygous or homozygous status of the fusion). Pericentrometric regions would pair the last, thus chiasma formation is strongly reduced in these areas contrary to what occurs in telocentric bivalents.
publishDate 2001
dc.date.none.fl_str_mv 2001
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/20.500.12110/paper_00180661_v134_n3_p245_Marti
url http://hdl.handle.net/20.500.12110/paper_00180661_v134_n3_p245_Marti
dc.language.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/2.5/ar
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/2.5/ar
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv Hereditas 2001;134(3):245-254
reponame:Biblioteca Digital (UBA-FCEN)
instname:Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron:UBA-FCEN
reponame_str Biblioteca Digital (UBA-FCEN)
collection Biblioteca Digital (UBA-FCEN)
instname_str Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
instacron_str UBA-FCEN
institution UBA-FCEN
repository.name.fl_str_mv Biblioteca Digital (UBA-FCEN) - Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
repository.mail.fl_str_mv ana@bl.fcen.uba.ar
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