Comparative Cytogenetics of Omophoita abbreviata and O. aequinoctialis (Coleoptera, Chrysomelidae, Alticini) from the Adolpho Ducke Forest Reserve in Brazilian Amazonia: Intrapopulation Variation in Karyotypes

2018 ◽  
Vol 156 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Leonardo G. Goll ◽  
Roberto F. Artoni ◽  
Maria C. Gross ◽  
Lucas R.A. Mello ◽  
Maria P.B. Coelho ◽  
...  
Keyword(s):  
Flea Beetle ◽  
Chromosomal Evolution ◽  
Typical Feature ◽  
Chromosome Morphology ◽  
Comparative Cytogenetics ◽  
Forest Reserve ◽  
Telomeric Sequences ◽  
Intrapopulation Variation ◽  
Central Amazonia ◽  
Intrapopulational Variation

The chromosomes of 2 flea beetle species from central Amazonia, Omophoita abbreviata and O. aequinoctialis (Alticini), were investigated through analysis of meiotic and mitotic cells. These species belong to the subtribe Oedionychina, a taxon that has unique cytogenetic features, such as giant sex chromosomes which are aligned at a distance during meiosis I (asynaptic). O. abbreviata and O. aequinoctialis have a meiotic formula of 10II + X + y, which is predominant in this subtribe. While the species of the genus Omophoita possess a relatively stable karyotype, a typical feature for Oedionychina, the present study identified inter- and intrapopulational variation in chromosome morphology, constitutive heterochromatin, and the presence and number of B chromosomes in O. aequinoctialis. In addition, FISH mapping of telomeric sequences revealed signals in the collochores, raising several questions on the chromosomal evolution in this group.

scholarly journals Rapid chromosomal evolution in the bush-cricket Gonatoxia helleri Hemp, 2016 (Orthoptera, Phaneropterinae)

2020 ◽  
Vol 14 (3) ◽  
pp. 417-435 ◽  
Author(s):  
Elżbieta Warchałowska-Śliwa ◽  
Beata Grzywacz ◽  
Anna Maryańska-Nadachowska ◽  
Klaus-Gerhard Heller ◽  
Claudia Hemp
Keyword(s):  
Chromosome Number ◽  
18S Rdna ◽  
Chromosomal Polymorphism ◽  
Chromosomal Evolution ◽  
Chromosome Morphology ◽  
Telomeric Sequences ◽  
C Banding ◽  
Interstitial Telomeric Sequences ◽  
Rdna Loci ◽  
Bush Crickets

Gonatoxia helleri Hemp, 2016 is one of the most widespread bush-crickets of the genus Gonatoxia Karsch, 1889 in East Africa. This species with seven large chromosomes (2n♂ = 7) differs from other representatives of the genus Gonatoxia drastically by its reduced chromosome number, the asymmetrical karyotype including karyomorphs rarely found in tettigoniids, as well as in irregularities in the course of meiosis. To better understand the origin of such an exceptional karyotype, chromosomes of 29 specimens from four populations/localities were studied using classical techniques, such as C-banding, silver impregnation, fluorochrome double staining and fluorescence in situ hybridization (FISH) technique with 18S rDNA and (TTAGG)n telomeric probes. FISH showed many 18S rDNA loci as well as interstitial telomeric sequences, where chromosome morphology varied in these components in terms of quantity and distribution. The 18S rDNA loci coincided with active NORs and C-banding patterns. We suggest that a combination of Robertsonian rearrangements and/or multiple common tandem fusions involving the same chromosomes contributed to the formation of this karyotype/karyomorphs. The results are the first step towards a better understanding of chromosomal reorganization and evolution within the genus Gonatoxia. Low chromosome number, together with the incidence of chromosomal polymorphism that is higher in G. helleri than previously reported in bush-crickets, implies that this species can be a valuable new model for cytogenetic and speciation studies. Our findings suggest that chromosomal translocations lead to diversification and speciation in this species and could be the driving force of adaptive radiation.

scholarly journals Comparative Cytogenetics Analysis Among Peckoltia Species (Siluriformes, Loricariidae): Insights on Karyotype Evolution and Biogeography in the Amazon Region

2021 ◽  
Vol 12 ◽  
Author(s):  
Kevin Santos da Silva ◽  
Augusto Cesar Paes de Souza ◽  
Ananda Marques Pety ◽  
Renata Coelho Rodrigues Noronha ◽  
Marcelo Ricardo Vicari ◽  
...  
Keyword(s):  
Karyotype Evolution ◽  
5S Rdna ◽  
Nucleolus Organizer ◽  
Valid Species ◽  
Left Bank ◽  
Comparative Cytogenetics ◽  
Telomeric Sequences ◽  
Nucleolus Organizer Regions ◽  
Karyotype Formula ◽  
Distal Location

Peckoltia is widely distributed genus in the Amazon and Orinoco basins and the Guiana Shield, containing 18 valid species, and distinct morphotypes still needing description in the scientific literature due to its great taxonomic complexity. This study performed a comparative chromosomal analysis of two undescribed Peckoltia species (Peckoltia sp. 3 Jarumã and Peckoltia sp. 4 Caripetuba) from the Brazilian Amazon using conventional chromosome bands methods and in situ localization of the repetitive DNA (5S and 18S rRNA and U1 snRNA genes and telomeric sequences). Both species presented 2n = 52 but differed in their karyotype formula, probably due to inversions or translocations. The nucleolus organizer regions (NORs) showed distal location on a probably homeologous submetacentric pair in both species, besides an extra signal in a subtelocentric chromosome in Peckoltia sp. 4 Caripetuba. Heterochromatin occurred in large blocks, with different distributions in the species. The mapping of the 18S and 5S rDNA, and U1 snDNA showed differences in locations and number of sites. No interstitial telomeric sites were detected using the (TTAGGG)n probes. Despite 2n conservationism in Peckoltia species, the results showed variation in karyotype formulas, chromosomal bands, and locations of repetitive sites, demonstrating great chromosomal diversity. A proposal for Peckoltia karyotype evolution was inferred in this study based on the diversity of location and number of chromosomal markers analyzed. A comparative analysis with other Peckoltia karyotypes described in the literature, their biogeography patterns, and molecular phylogeny led to the hypothesis that the derived karyotype was raised in the left bank of the Amazon River.

Cytogenetics of Four Species of the Green Clade Aplastodiscus Lutz, 1950 (Anura: Cophomantinae): New Insights into the Chromosomal Evolution of the Genus

2021 ◽  
pp. 1-7
Author(s):  
Késsia L. Souza ◽  
Marco A. Peixoto ◽  
Cynthia A.V. Barreto ◽  
Renato N. Feio ◽  
Jorge A. Dergam
Keyword(s):  
18S Rdna ◽  
Chromosome Pair ◽  
Chromosomal Evolution ◽  
Chromosome Morphology ◽  
Small Chromosome ◽  
Tree Frog ◽  
Chromosome Fusion ◽  
Clade B ◽  
Number Variation ◽  
Molecular Cytogenetic Techniques

The tree frog <i>Aplastodiscus</i> is a Neotropical taxon that encompasses 15 species in the Atlantic forest biome, with one isolated species in the Central Brazilian Cerrado. To date, only 8 species have been karyotyped, showing high levels of diploid number variation, which allowed clustering species in chromosome number groups: 2n = 24 (<i>Aplastodiscus perviridis</i> group), 2n = 22 (<i>Aplastodiscus albofrenatus</i> group), 2n = 20, and 2n = 18 (both within <i>Aplastodiscus albosignatus</i> group). This study aims to report karyotypic information on 4 species from the last 2 groups using classical and molecular cytogenetic techniques and hypothesize chromosomal evolutionary trends within the species groups. <i>Aplastodiscus weygoldti</i> showed 2n = 22; Ag-NOR and FISH 18S rDNA signals were located in the interstitial region of the short arms of chromosome pair 6. <i>Aplastodiscus cavicola, Aplastodiscus</i> sp. 4, and <i>Aplastodiscus</i> sp. 6 showed 2n = 18; Ag-NOR and FISH 18S rDNA bands were located in the terminal region of the long arm of chromosome pair 9. Our results support multiple and independent chromosome fusion events within <i>Aplastodiscus</i>, including a new chromosome fission event<i>.</i> Ag-NOR and FISH 18S rDNA patterns were restricted to the small chromosome pairs, similar to the other species within this genus, and confirm overall chromosome morphology conservation among the genera of Cophomantinae.

Distribution of Telomeric Sequences (TTAGGG)n in Rearranged Chromosomes of Phyllotine Rodents (Cricetidae, Sigmodontinae)

2015 ◽  
Vol 147 (4) ◽  
pp. 247-252 ◽  
Author(s):  
Cecilia Lanzone ◽  
Carolina Labaroni ◽  
Natalia Suárez ◽  
Daniela Rodríguez ◽  
Macarena L. Herrera ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Chromosomal Evolution ◽  
Robertsonian Translocations ◽  
Telomeric Sequences ◽  
Molecular Cytogenetic ◽  
Interstitial Telomeric Sequences ◽  
Robertsonian Rearrangements ◽  
Recent Origin ◽  
Chromosome Fusions ◽  
Molecular Cytogenetic Techniques

Phyllotines are sigmodontine rodents endemic to South America with broad genetic variability, Robertsonian polymorphisms being the most frequent. Moreover, this taxon includes a species with multiple sex chromosomes, which is infrequent in mammals. However, molecular cytogenetic techniques have never been applied to phyllotines to elucidate their karyotypic evolution. We studied the chromosomes of 4 phyllotine species using FISH with a pantelomeric probe (TTAGGG)n. Graomys griseoflavus, Eligmodontia puerulus, and E. morgani are polymorphic for Robertsonian translocations, whereas Salinomys delicatus possesses XX/ XY1Y2 sex chromosomes. Telomeric signals were detected at both ends of all chromosomes of the studied species. In S. delicatus interstitial telomeric sequences (ITS) were observed in the 3 major chromosome pairs, which are equidistant from one of the telomeres in these chromosomes. These results suggest that ITS are important in the reshuffling of the highly derived karyotype of S. delicatus. Considering the phylogeny of phyllotines, the Robertsonian rearrangements of G. griseoflavus, E. puerulus, and E. morgani possibly represent chromosome fusions which have occurred independently. The pericentromeric regions of the biarmed chromosomes of these species do not contain telomeric sequences characteristic for strict fusions of recent origin, suggesting a common pattern of telomeric repeat loss during chromosomal evolution of these rodents.

Comparative Cytogenetics of the Congo African Grey Parrot (Psittacus erithacus)

2015 ◽  
Vol 147 (2-3) ◽  
pp. 144-153 ◽  
Author(s):  
Cassandra Seibold-Torres ◽  
Elaine Owens ◽  
Renuka Chowdhary ◽  
Malcolm A. Ferguson-Smith ◽  
Ian Tizard ◽  
...  
Keyword(s):  
Central Africa ◽  
Habitat Destruction ◽  
Comparative Cytogenetics ◽  
African Grey Parrot ◽  
Telomeric Sequences ◽  
Psittacus Erithacus ◽  
Molecular Cytogenetic ◽  
Grey Parrot ◽  
Avian Genomes ◽  
Ancestral Type

The Congo African grey parrot (Psittacus erithacus, PER) is an endemic species of Central Africa, valued for its intelligence and listed as vulnerable due to poaching and habitat destruction. Improved knowledge about the P. erithacus genome is needed to address key biological questions and conservation of this species. The P. erithacus genome was studied using conventional and molecular cytogenetic approaches including Zoo-FISH. P. erithacus has a ‘typical' parrot karyotype with 2n = 62-64 and 8 pairs of macrochromosomes. A distinct feature was a sharp macro-microchromosome boundary. Telomeric sequences were present at all chromosome ends and interstitially in PER2q, the latter coinciding with a C-band. NORs mapped to 4 pairs of microchromosomes which is in contrast to a single NOR in ancestral type avian karyotypes. Zoo-FISH with chicken macrochromosomes GGA1-9 and Z revealed patterns of conserved synteny similar to many other avian groups, though neighboring synteny combinations of GGA6/7, 8/9, and 1/4 were distinctive only to parrots. Overall, P. erithacus shared more Zoo-FISH patterns with neotropical macaws than Australian species such as cockatiel and budgerigar. The observations suggest that Psittaciformes karyotypes have undergone more extensive evolutionary rearrangements compared to the majority of other avian genomes.

Spatial patterns in the understorey shrub genus Psychotria in central Amazonia: effects of distance and topography

2005 ◽  
Vol 21 (4) ◽  
pp. 363-374 ◽  
Author(s):  
V. F. Kinupp ◽  
William E. Magnusson
Keyword(s):  
Species Composition ◽  
Minimum Distance ◽  
Local Density ◽  
Ecological Factors ◽  
Analysis Of Covariance ◽  
Habitat Specialization ◽  
Forest Reserve ◽  
Plot Size ◽  
Central Amazonia ◽  
Species Abundances

We evaluated the effects of topography on the distribution of understorey herbs, shrubs and small trees of the pantropical genus Psychotria (Rubiaceae) in a 10000-ha rain-forest reserve in central Amazonia. As plots were long and thin, and followed altitudinal isoclines, we were able to avoid the trade off between plot size and precision of measurement of topographical variables. The minimum distance between plots (1 km) was sufficient to avoid spatial autocorrelation in topographical variables. However, indices of plot similarity based on species composition were spatially autocorrelated to distances of at least 4 km. Although Multivariate Analysis of Covariance (MANCOVA) indicated significant effects of altitude, slope, and watershed on species composition within plots, topographical variables were generally poor surrogates for species distributions. Differences between eastern and western watersheds within the reserve were not due to distance effects, and most species occurred in both watersheds, indicating that differences in species assemblages between watersheds are determined by ecological factors. Habitat specialization and local density were not clearly associated with rarity. At scales of 1–10 km, both distance and habitat affect the distribution of understorey shrubs of the genus Psychotria, but much of the variation in species abundances remains unexplained.

scholarly journals Molecular Composition of Heterochromatin and Its Contribution to Chromosome Variation in the Microtus thomasi/Microtus atticus Species Complex

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 807
Author(s):  
Michail Rovatsos ◽  
Juan Alberto Marchal ◽  
Eva Giagia-Athanasopoulou ◽  
Antonio Sánchez
Keyword(s):  
Repetitive Dna ◽  
Species Complex ◽  
Sex Chromosome ◽  
Chromosomal Rearrangements ◽  
Chromosome Morphology ◽  
Dna Motifs ◽  
Telomeric Sequences ◽  
Chromosome Races ◽  
Chromosomal Races ◽  
Dna Elements

The voles of the Microtus thomasi/M. atticus species complex demonstrate a remarkable variability in diploid chromosomal number (2n = 38–44 chromosomes) and sex chromosome morphology. In the current study, we examined by in situ hybridization the topology of four satellite DNA motifs (Msat-160, Mth-Alu900, Mth-Alu2.2, TTAGGG telomeric sequences) and two transposons (LINE, SINE) on the karyotypes of nine chromosome races (i.e., populations with unique cytogenetic traits) of Microtus thomasi, and two chromosomal races of M. atticus. According to the topology of the repetitive DNA motifs, we were able to identify six types of biarmed chromosomes formed from either Robertsonian or/and tandem fusions. In addition, we identified 14 X chromosome variants and 12 Y chromosome variants, and we were able to reconstruct their evolutionary relations, caused mainly by distinct mechanisms of amplification of repetitive DNA elements, including the telomeric sequences. Our study used the model of the Microtus thomasi/M. atticus species complex to explore how repetitive centromeric content can alter from chromosomal rearrangements and can shape the morphology of sex chromosomes, resulting in extensive inter-species cytogenetic variability.

scholarly journals Chromosome spreading of the (TTAGGG)n repeats in the Pipa carvalhoi Miranda-Ribeiro, 1937 (Pipidae, Anura) karyotype

2019 ◽  
Vol 13 (3) ◽  
pp. 297-309 ◽  
Author(s):  
Michelle Louise Zattera ◽  
Luana Lima ◽  
Iraine Duarte ◽  
Deborah Yasmin de Sousa ◽  
Olívia Gabriela dos Santos Araújo ◽  
...  
Keyword(s):  
Chromosome Pair ◽  
Diploid Number ◽  
Centromeric Region ◽  
Chromosomal Evolution ◽  
Unique Combination ◽  
Significant Component ◽  
Aquatic Life ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Chromosome Spreading

Pipidae is a clade of Anura that diverged relatively early from other frogs in the phylogeny of the group. Pipids have a unique combination of morphological features, some of which appear to represent a mix of adaptations to aquatic life and plesiomorphic characters of Anura. The present study describes the karyotype of Pipa carvalhoi Miranda-Ribeiro, 1937, including morphology, heterochromatin distribution, and location of the NOR site. The diploid number of P. carvalhoi is 2n=20, including three metacentric pairs (1, 4, 8), two submetacentric (2 and 7), three subtelocentric (3, 5, 6), and two telocentric pairs (9 and 10). C-banding detected centromeric blocks of heterochromatin in all chromosome pairs and the NOR detected in chromosome pair 9, as confirmed by FISH using the rDNA 28S probe. The telomeric probes indicated the presence of interstitial telomeric sequences (ITSs), primarily in the centromeric region of the chromosomes, frequently associated with heterochromatin, suggesting that these repeats are a significant component of this region. The findings of the present study provide important insights for the understanding of the mechanisms of chromosomal evolution in the genus Pipa, and the diversification of the Pipidae as a whole.

scholarly journals Breakage–fusion–bridge cycles and de novo telomere formation on broken chromosomes in maize callus cultures

Genome ◽  
2016 ◽  
Vol 59 (6) ◽  
pp. 367-378 ◽  
Author(s):  
Janay A. Santos-Serejo ◽  
Margarida L.R. Aguiar-Perecin
Keyword(s):  
De Novo ◽  
Chromosomal Evolution ◽  
Callus Cultures ◽  
Chromosome 7 ◽  
Telomeric Sequences ◽  
Chromosome Healing ◽  
Regenerated Plants ◽  
The Stability ◽  
Maize Callus

Breakpoints involved in chromosome alterations associated with heterochromatin have been detected in maize plants regenerated from callus culture. A cytogenetic analysis of plants regenerated from a maize callus was performed aiming to analyze the stability of a chromosome 7 bearing a deficiency-duplication (Df-Dp), which was interpreted as derived from a chromatid type breakage–fusion–bridge (BFB) cycle. The Df-Dp chromosome 7 was stable in mitotic and meiotic cells of the regenerated plants. Fluorescence in situ hybridization showed signals of telomeric sequences on the broken chromosome arm and provided evidence of de novo telomere formation. The stability of two types of altered chromosome 7 was investigated in C-banded metaphases from samples of the original callus that were collected during a period of 30–42 months after culture initiation. New alterations involving heterochromatic knobs of chromosomes 7 and 9 were observed. The aberrant chromosomes were stable in the subcultures, thus providing evidence of broken chromosome healing. The examination of anaphases showed the presence of bridges, which was consistent with the occurrence of BFB cycles. De novo telomere formation occurred in euchromatic and heterochromatic chromosome termini. The results point to events of chromosomal evolution that might occur in plants.

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