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445 results for “karyotype”
Fig. 2 in Cytogenetical analyses in three fish species of the genus Pimelodus (Siluriformes: Pimelodidae) from rio São Francisco: considerations about the karyotypical evolution in the genus
Fig. 2. Somatic chromosome metaphases of P. fur (a, d), P. maculatus (b, e) and Pimelodus sp. (c, f) submitted to: C banding (a, b, c) and staining with CMA (d, e, f). The major arrows indicate the NOR-bearing pairs. NOR association (b, f) and NOR size 3 heteromorphism (a) are exemplified. The arrows indicate positive chromosome regions corresponding with heterochromatin sites after treatment with fluorochrome and the arrowheads indicate a pair of metacentric chromosomes with both telomeres heterochromatic.
Fig. 2. Karyotypes treated with the C-banding technique. a in Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps (Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela
Fig. 2. Karyotypes treated with the C-banding technique. a) Prochilodus mariae - "B" indicates a supernumerary microchromosome; b) Semaprochilodus kneri; and c) Semaprochilodus laticeps.
Fig. 1 in Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps (Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela
Fig. 1. Karyotypes of: a) Prochilodus mariae with 2n=54 chromosomes plus two supernumerary microchromosomes (B); b) Semaprochilodus kneri with 2n=54 chromosomes; and c) Semaprochilodus laticeps with 2n=54 chromosomes. In the insets, silver stained chromosomes with the nucleolus organizer regions in pair 2. Bars = 10 µm.
Figure 1 in Karyotype analysis of two oribatid mite species (Acari: Oribatida)
Figure 1. Photomicrograph of mitotic metaphase chromosomes, A-D. Hermanniella gibber, E-I. Oribotritia hermanni
Ancestral reconstruction of sunflower karyotypes reveals non-random chromosomal evolution
<p>Mapping the chromosomal rearrangements between species can inform our understanding of genome evolution, reproductive isolation, and speciation. Here we present a novel algorithm for identifying regions of synteny in pairs of genetic maps, which is implemented in the accompanying R package, syntR. The syntR algorithm performs as well as previous methods while being systematic and repeatable and can be used to map chromosomal rearrangements in any group of species. In addition, we present a systematic survey of chromosomal rearrangements in the annual sunflowers, which is a group known for extreme karyotypic diversity. We build high-density genetic maps for two subspecies of the prairie sunflower<i>,</i> <i>Helianthus</i> <i>petiolaris</i> ssp. <i>petiolaris</i> and <i>H. petiolaris</i> ssp. <i>fallax.</i> Using <i>syntR</i>, and we identify blocks of synteny between these two subspecies and previously published high-density genetic maps. We reconstruct ancestral karyotypes for annual sunflowers using those synteny blocks and conservatively estimate that there have been 7.9 chromosomal rearrangements per million years – a high rate of chromosomal evolution. Although the rate of inversion is even higher than the rate of translocation in this group, we further find that every extant karyotype is distinguished by between 1 and 3 translocations involving only 8 of the 17 chromosomes. This non-random exchange suggests that specific chromosomes are prone to translocation and may thus contribute disproportionately to widespread hybrid sterility in sunflowers. These data deepen our understanding of chromosome evolution and confirm that <i>Helianthus</i> has an exceptional rate of chromosomal rearrangement that may facilitate similarly rapid diversification.</p>
Data from: Repositioning of centromere-associated repeats during karyotype evolution in Oryzias fishes
<p>The karyotype, which is the number and shape of chromosomes, is a fundamental characteristic of all eukaryotes. Karyotypic changes play an important role in many aspects of evolutionary processes, including speciation. In organisms with monocentric chromosomes, it was previously thought that chromosome number changes were mainly caused by centric fusions and fissions, whereas chromosome shape changes, that is changes in arm numbers, were mainly due to pericentric inversions. However, recent genomic and cytogenetic studies have revealed examples of alternative cases, such as tandem fusions and centromere repositioning, found in the karyotypic changes within and between species. Here, we employed comparative genomic approaches to investigate whether centromere repositioning occurred during karyotype evolution in medaka fishes. In the medaka family (Adrianichthyidae), the three phylogenetic groups differed substantially in their karyotypes. The <em>Oryzias latipes</em> species group has larger numbers of chromosome arms than the other groups, with most chromosomes being metacentric. The <em>O. javanicus</em> species group has similar numbers of chromosomes to the <em>O. latipes</em> species group, but smaller arm numbers, with most chromosomes being acrocentric. The <em>O. celebensis</em> species group has fewer chromosomes than the other two groups and several large metacentric chromosomes that were likely formed by chromosomal fusions. By comparing the genome assemblies of <em>O. latipes</em>, <em>O. javanicus</em>, and <em>O. celebensis</em>, we found that repositioning of centromere-associated repeats might be more common than simple pericentric inversion. Our results demonstrated that centromere repositioning may play a more important role in karyotype evolution than previously appreciated.</p>
Fig. 3 in Comparative Analysis Of Karyotypes Of Two Cryptic Species Of Pelobatid Frogs (Amphibia, Anura) Of Ukraine
Fig. 3. Absolute length of chromosomes in spadefoots (Pelobates) of Ukraine. nm.
Fig. 1 in The Thick-Clawed Crayfish, Astacus Pachypus (Crustacea, Decapoda, Astacidae), In Ukraine: Karyotype, Allozymes And Morphological Parameters
Fig. 1. Locations of samples of four crayfish species in Ukraine.
Figure 3 in A new opilioacarid species (Parasitiformes: Opilioacarida) from Crete (Greece) with notes on its karyotype
Figure 3 Opilioacarus thalerin. sp., dorsal view on an adult specimen in ethanol.
Figure 2 in A new opilioacarid species (Parasitiformes: Opilioacarida) from Crete (Greece) with notes on its karyotype
Figure 2 Habitat of Opilioacarus thalerin. sp.
Supplementary material 1 from: Scacchetti P, Pansonato-Alves J, Utsunomia R, Oliveira C, Foresti F (2011) Karyotypic diversity in four species of the genus Gymnotus Linnaeus, 1758 (Teleostei, Gymnotiformes, Gymnotidae): physical mapping of ribosomal genes and telomeric sequences. Comparative Cytogenetics 5(3): 223-235. https://doi.org/10.3897/compcytogen.v5i3.1375
Nexus file of aligned COI and COII nucleotide sequences.
Figure 1 in Unveiling the genetic diversity of bicolored-spined porcupines (Rodentia: Erethizontidae): a novel karyotype, population structuring, and evolutionary insights
Figure 1. Map of part of South America with collecting localities of C. bicolor specimens with sequences on the GenBank (Black circles), generated in the present study (triangle), others register of occurrences (white circles), and type locality (star). Gray area represents the Amazon Biome. ARG = Argentina, BOL = Bolivia, BRA = Brazil, PER = Peru.
Figure 4 in Unveiling the genetic diversity of bicolored-spined porcupines (Rodentia: Erethizontidae): a novel karyotype, population structuring, and evolutionary insights
Figure 4. Topology of median joining on top of the map showing the current separation of C. bicolor populations by the rivers Ucayali and Beni/Madre de Dios. Circles are haplotypes and its dimension are proportional to the number of shared sequences. Numbers in the segments connecting the circles are nucleotide substitutions and black circle is the median vector. For haplotypes localities see figure 2. BOL = Bolivia, BRA = Brazil, PER = Peru.
Figure 3 in Unveiling the genetic diversity of bicolored-spined porcupines (Rodentia: Erethizontidae): a novel karyotype, population structuring, and evolutionary insights
Figure 3. Maximum likelihood phylogenetic tree. Symbols near nodes represent Bootstrap values: black circles (90-100%), white circles (80-89%), white squares (70-79%), black square (66%). BOL = Bolivia, BRA = Brazil, COL = Colombia, ECU = Ecuador, GUF = French Guiana, MEX = Mexico, PAR = Paraguay, PER = Peru.
Figure 2 in Unveiling the genetic diversity of bicolored-spined porcupines (Rodentia: Erethizontidae): a novel karyotype, population structuring, and evolutionary insights
Figure 2. Conventional stained karyotypes of Coendou (Sphiggurus) bicolor male LBCE21287 (above) and female LBCE21289 (below) from Brazilian Acre state with 2n = 52 and FN = 82. The X and Y are sexual chromosomes.
Fig. 2. Karyotypes showing C in Microstructural chromosome reorganization in the genus Trichomycterus (Siluriformes: Trichomycteridae)
Fig. 2. Karyotypes showing C Band of the species of Trichomycterus analyzed.
FIGURE 1 in Chromosome analysis in Saccodon wagneri (Characiformes) and insights into the karyotype evolution of Parodontidae
FIGURE 1 | Map of Ecuador, highlighting the sampling site of Saccodon wagneri.
Figure 6 in Comparison of natural histories and karyotypes of two closely related ant-eating spiders, Zodarion hamatum and Z. italicum (Araneae, Zodariidae)
Figure 6. Male karyograms. (A) Zodarion italicum (mitotic metaphase); (B) Z. hamatum (anaphase I).
Fig. 1 in Pleistocene karyotypic divergence in Hoplias malabaricus (Bloch, 1794) (Teleostei: Erythrinidae) populations in southeastern Brazil
Fig. 1. Lacustrine system of the middle rio Doce. Triangles indicate sampled lakes.
Figure 2 in Karyotype analysis of two oribatid mite species (Acari: Oribatida)
Figure 2. The monoploid ideograms of Hermanniella gibber (A) and Oribotritia hermanni (B).
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International Brain Laboratory public data
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OpenNeuro
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