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Evolutionary cytogenetics in Heteroptera
Behaviour of ring bivalents in holokinetic systems: Alternative sites of spindle attachment in Pachylis argentinus and Nezara viridula (Heteroptera)
- A. Papeschi, L. M. Mola, M. J. Bressa, E. Greizerstein, V. Lia, L. Poggio
- BiologyChromosome Research
This work proposes a new mode of segregation for ring bivalents: when the chromosome pair bears a secondary constriction, it is not essential that one of the chiasmata releases first since these regions or repetitive DNA sequences adjacent to them become functional as alternative sites for microtubule attachment and they undertake chromosome segregation to the poles during anaphase I.
Meiosis and fluorescent banding in Edessa meditabunda and E. rufomarginata (Heteroptera: Pentatomidae: Edessinae)
The results in E. meditabunda together with previous reports in other species of the order led us to suggest that the metaphase plate arrangement is more liable to variation at the first meiotic division than at the second one, when it is almost constant.
Sex Chromosome Evolution in Cotton Stainers of the Genus Dysdercus (Heteroptera: Pyrrhocoridae)
The hypothesis that the neo-X chromosome evolved by insertion of the original X chromosome into 1 NOR-bearing autosome in an ancestor carrying the X0 system is supported, as a consequence, the homologue of this NOR-autosome became the Neo-Y chromosome.
Heterochromatin characterization in five species of Heteroptera
There should exist some constraints to the acquisition and/ or accumulation of heterochromatin in their karyotypes, according to the chiasma frequency and distribution in the five species.
Cytogenetic studies in Pentatomidae (Heteroptera): A review
A bibliographic review of the chromosome number and sex determining system of 294 species and subspecies belonging to 121 genera within the subfamilies Asopinae, Discocephalinee, Edessinaes, Pentatominae), Phyllocephalinae and Podopinaes is presented.
Heterochromatin heteromorphism in Holhymenia rubiginosa (Heteroptera: Coreidae)
The C-band pattern in individuals of Holhymenia rubiginosa from different populations collected in different years is analyzed and it is suggested that heterochromatin should be selectively neutral in H. rubIGinosa.
Karyotype and meiotic behaviour of the holokinetic chromosomes of six Argentine species of Pentatomidae (Heteroptera)
It is suggested that ring bivalents are not so uncommon as it has been previously supported and some differences in the karyotype and meiotic behaviour are encountered (relative size of sex chromosomes, characteristics of the diffuse stage).
CYTOGENETIC HETEROGENEITY IN COMMON HAPLOGYNE SPIDERS FROM ARGENTINA (ARACHNIDA, ARANEAE)
The results show that Haplogynae present high cytogenetic heterogeneity: species with holokinetic chromosomes as well as species with monocentric chromosomes, and species with low diploid numbers, achiasmatic meiosis and proximal chiasma localization.
The significance of cytogenetics for the study of karyotype evolution and taxonomy of water bugs (Heteroptera, Belostomatidae) native to Argentina
The hypothesis that all species of Belostoma with multiple sex chromosome systems preserve NORs in autosomal bivalents is supported and the karyotype analyses allow the cytogenetic characterization and identification of these species belonging to a difficult taxonomic group.