Heterochromatin heterogeneity and rapid divergence of the sex chromosomes in Chorthippus parallelus parallelus and C. p. erythropus (Orthoptera)

Genome ◽  
1993 ◽  
Vol 36 (3) ◽  
pp. 542-547 ◽  
Author(s):  
J. L. Bella ◽  
L. Serrano ◽  
G. M. Hewitt ◽  
J. Gosálvez
Keyword(s):  
Sex Chromosomes ◽  
Hybrid Zones ◽  
Mitotic Chromosomes ◽  
Chromomycin A3 ◽  
Repetitive Dnas ◽  
Chorthippus Parallelus ◽  
C Banding ◽  
Structure And Dynamics ◽  
Rates Of Evolution ◽  
Rapid Divergence

Mitotic chromosomes from individuals of a Pyrenean hybrid zone between two subspecies of the grasshopper Chorthippus parallelus have been pretreated as for C-banding and subsequently stained with 4,6-diamidino-2-phenylindole (DAPI) and (or) Chromomycin A3 (CMA). The results, which are different from those obtained with Giemsa C-banding or standard DAPI – CMA treatments show (i) hidden heterochromatic heterogeneity that may be correlated with the existence of distinct families of repetitive DNAs, (ii) information about the possible independent origin of the three detected types of heterochromatin, and (iii) a further marker difference between the sex chromosomes of these two subspecies. This last result leads us to discuss the possible differential rates of evolution of sex chromosomes and autosomes in these subspecies and provides us with a new tool for the study of the structure and dynamics of this hybrid zone.Key words: hybrid zones, Orthoptera, cytogenetics, heterochromatin, fluorescence.

Fluorescence banding in mitotic and meiotic chromosomes of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 580-588 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Silver Staining ◽  
Ceratitis Capitata ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
The Mediterranean

Mitotic and meiotic chromosomes of the Mediterranean fruit fly, Ceratitis capitata, were studied using three counterstain-enhanced fluorescence staining methods. The tristaining technique allowed chromomycin A3 (CMA) and distamycin – diamidinophenylindole (DA–DAPI) fluorescence to be observed on the same chromosomes. DAPI–actinomycin D (DAPI–AMD) fluorescence was also carried out. These techniques were complemented with quinacrine staining and C-banding. The results were compared with earlier data on silver staining. The sex chromosomes, particularly the X chromosome, show great banding detail with extensive longitudinal differentiation in mitotic chromosomes. GC- and AT-specific fluorescence is not found in the expected reciprocal pattern at all sites. Comparison with C-banding and silver staining shows that intense fluorescence occurs in lightly C banded regions and silver bands correspond to fluorescent bands rather than nucleolar organizers. The combination of staining data suggests that much of the X chromosome has characteristics intermediate between heterochromatin and euchromatin. Meiotic X chromosomes show much less detail and reduced fluorescence intensity but can still be easily traced throughout meiosis and spermatogenesis.Key words: fluorescence banding, sex chromosomes, Mediterranean fruit fly, Ceratitis capitata.

Cytological characterisation of heterochromatin in mitotic and meiotic chromosomes of the Old World screwworm fly, Chrysomya bezziana (Diptera: Calliphoridae)

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 631-637 ◽  
Author(s):  
D. G. Bedo
Keyword(s):  
Sex Chromosomes ◽  
Mitotic Chromosomes ◽  
Old World ◽  
Screwworm Fly ◽  
C Banding ◽  
Meiotic Chromosomes ◽  
Bright Fluorescence ◽  
Y Chromosomes ◽  
Background Staining ◽  
Chrysomya Bezziana

Mitotic and meiotic chromosomes of the Old World screwworm fly, Chrysomya bezziana, were studied using C-banding and quinacrine and counterstain-enhanced fluorescence techniques. The five autosomes in the karyotype are evenly graded in size, with somewhat variable arm ratios. Distinguishing all autosomes on these features alone can be difficult. C-banding produces small centromeric bands in the autosomes, whereas the much longer X and Y chromosomes have extensive dark C-band blocks with intermediate background staining. Most bright fluorescence occurs in the sex chromosomes, particularly the X chromosome, which has remarkable banding detail. Band resolution is greatly increased in mitotic metaphase cells from embryos. Quinacrine staining of mitotic chromosomes produces bright fluorescence at the centromere regions of chromosomes 2, 3, and 4, assisting in their identification. Meiotic chromosomes have distinctly reduced brightness and resolution of fluorescent bands and show marked chromatid asynapsis in the brighter regions of the sex chromosomes. Fluorochromes staining A∙T-rich DNA (quanacrine and 4,6-diamidino-2-phenylindole (DAPI)) produce bright staining in a large proportion of the sex chromosomes. By contrast chromomycin, which binds preferentially to G∙C-rich DNA, stains a much smaller proportion of the sex chromosomes than expected from reciprocal staining. Together with the asynapsis data this indicates that much of the heterochromatin in the sex chromosomes has unusual structural properties.Key words: Chrysomya bezziana, screwworm, karyotype, C-banding, fluorescence, heterochromatin.

The influence of fixation on the morphology of mitotic chromosomes

1986 ◽  
Vol 28 (4) ◽  
pp. 536-539 ◽  
Author(s):  
Axel J. J. Dietrich
Keyword(s):  
Acetic Acid ◽  
Chemical Composition ◽  
Strong Influence ◽  
Chromosome Structure ◽  
Human Lymphocytes ◽  
Chromosome Morphology ◽  
Mitotic Chromosomes ◽  
Specific Chemical ◽  
C Banding ◽  
Sister Chromatids

It is well known that there is a strong influence of fixation, i.e., acetic methanol versus formaldehyde, on the chromosome morphology at stages of the first meiotic division. In this study the influence of both these types of fixation on the morphology of mitotic chromosomes was examined in human lymphocytes. After methanol – acetic acid (3:1) fixation, the chromosomes show the "classical" condensed shape in which it is not always possible to recognize the two sister chromatids. These chromosomes are accessible to the conventional G-, R-, and C-banding techniques. After formaldehyde fixation at a relatively high pH, the chromosomes are thinner and longer (two to six times) when compared with chromosomes following methanol – acetic acid fixation. They show a scaffold-like morphology, sometimes with a halo of thin material around it. In all cases the two sister chromatids could be recognized. This chromosome structure could be easily stained with silver, Giemsa, 4,6-diamino-2-phenyl-indole (DAPI), and fluorescein isocyanate isomere 1 (FITC). The results obtained following these stainings gave no indication to any specific chemical composition of a probable central scaffold. The scaffold-like structures were not accessible to G-, R-, or C-banding techniques. The only effect observed following these banding techniques was the disappearance of the halo of thin material around the central scaffold-like structure.Key words: chromosome structure, fixation influence, human lymphocytes.

CHROMOSOMES AND DNA OF MICROTUS II. CONFIRMATION OF DELETION OF CONSTITUTIVE HETEROCHROMATIN IN M. AGRESTIS CELLS IN VITRO

1977 ◽  
Vol 19 (3) ◽  
pp. 537-541 ◽  
Author(s):  
J. E. K. Cooper
Keyword(s):  
Somatic Cell ◽  
Cell Line ◽  
Cell Lines ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Constitutive Heterochromatin ◽  
The Other ◽  
Microtus Agrestis ◽  
C Banding

The distribution of constitutive heterochromatin has been examined by C-banding in two somatic cell lines, grown in vitro, from a female Microtus agrestis. One line retains one intact X chromosome together with the short arm of the other X chromosome, while the other cell line retains only the short arm of one X chromosome. Thus, each cell line has lost substantial amounts of heterochromatin from the sex chromosomes, but this material has been deleted from the cells, and not translocated to other chromosomes. Nonetheless, both cell lines continue to propagate well in vitro.

scholarly journals Restricted X chromosome introgression and support for Haldane's rule in hybridizing damselflies

2021 ◽  
Author(s):  
Janne Swaegers ◽  
Rosa Ana Sanchez-Guillen ◽  
Pallavi Chauhan ◽  
Maren Wellenreuther ◽  
Bengt Hansson
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Hybrid Zones ◽  
Haldane’S Rule ◽  
Haldane's Rule ◽  
Genome Wide ◽  
Determination System ◽  
Heterogametic Sex ◽  
Sex Determination System ◽  
Genomic Introgression

Contemporary hybrid zones act as natural laboratories for the investigation of species boundaries and allow to shed light on the little understood roles of sex chromosomes in species divergence. Sex chromosomes are considered to function as a hotspot of genetic divergence between species; indicated by less genomic introgression compared to autosomes during hybridisation. Moreover, they are thought to contribute to Haldane's rule which states that hybrids of the heterogametic sex are more likely to be inviable or sterile. To test these hypotheses, we used contemporary hybrid zones of Ischnura elegans, a damselfly species that has been expanding its range into the northern and western regions of Spain, leading to chronic hybridization with its sister species Ischnura graellsii. We analysed genome-wide SNPs in the Spanish I. elegans and I. graellsii hybrid zone and found (i) that the X chromosome shows less genomic introgression compared to autosomes and (ii) that males are underrepresented among admixed individuals as predicted by Haldane's rule. This is the first study in Odonata that suggests a role of the X chromosome in reproductive isolation. Moreover, our data adds to the few studies on species with X0 sex determination system and contradicts the hypothesis that the absence of a Y chromosome causes exceptions to Haldane's rule.

KARYOLOGICAL RELATIONSHIPS IN TURTLES (REPTILIA: CHELONIA)

1972 ◽  
Vol 14 (4) ◽  
pp. 859-868 ◽  
Author(s):  
A. Dean Stock
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Mitotic Chromosomes ◽  
Meiotic Chromosomes ◽  
Telocentric Chromosomes ◽  
Chromosome Karyotype

The mitotic chromosomes of 33 species of chelonians representing 22 genera and six families were investigated. Chromosome number and morphology are the same for most members of a given family and range from 66 in Trionyx to 34 in Pelomedusa. Most emydid genera have 50 chromosomes. The karyotype of Chelydra (2n = 52) is similar to those of some testudinid and emydid genera and is unlike the 56 chromosome karyotype of kinosternid turtles. The three genera of tortoises examined, Gopherus, Testudo, and Geochelone, have 52 chromosomes, but Gopherus differs in karyotypic details. The karyotype of Geochelone is like that of Chelydra and the 52 chromosome genera of emydid turtles. The African pleurodiran Pelomedusa has three additional pairs of small acrocentric or telocentric chromosomes not present in the earlier described karyotype of Podocnemis. Examination of meiotic chromosomes revealed frequencies of chiasmata formation similar to those reported earlier. Sex chromosomes were not distinguishable.

scholarly journals Chromosomal polymorphism in 12 populations of Mikania micrantha (Compositae)

1999 ◽  
Vol 22 (3) ◽  
pp. 433-444 ◽  
Author(s):  
Eliane M.D. Maffei ◽  
M.A. Marin-Morales ◽  
P.M. Ruas ◽  
C.F. Ruas ◽  
N.I. Matzenbacher
Keyword(s):  
Chromosomal Polymorphism ◽  
The United States ◽  
B Chromosomes ◽  
Mitotic Chromosomes ◽  
Mikania Micrantha ◽  
Perennial Weed ◽  
C Banding ◽  
Size Number ◽  
Chromosomal Differentiation ◽  
First Time

Mikania micrantha is a climbing perennial weed of the family Asteraceae, with a vast distribution from South America to south of the United States. This species is widely distributed throughout Brazil, where it shows little morphological variation. Mitotic chromosomes of 12 populations of M. micrantha derived from several Brazilian sites were studied using Feulgen staining and C-banding. The populations included eight diploid (2n = 36 and 42) and four tetraploid (2n = 72) cytotypes. Chromosome numbers of 2n = 36 and 2n = 42 are reported for the first time for M. micrantha. These populations had a secondary constriction in the middle of the larger arm of chromosome pair 1, following the same pattern described for all Mikania species analyzed so far. Numerical and structural variation of the chromosomes was quite common among the karyotypes and nearly all cytotypes differed from each other in some aspect. Most of the chromosomal differentiation may be attributed to inversions and addition or deletion of DNA fragments. C-banding, applied to three of the 12 populations, also revealed polymorphism in the distribution of heterochromatin. Additionally, one to 14 supernumerary or B-chromosomes were observed. The Bs were detected in six of the 12 populations and varied in size, number, and structure among karyotypes and also among cells of the same root meristem. The B chromosomes were also heterochromatic, showing a C-banding pattern similar to the A chromosomes, and suggesting that they may be derived from the chromosomes of the A complement.

Karyotype and C-banding pattern of mitotic chromosomes in alfalfa, Medicago sativa L.

1995 ◽  
Vol 114 (5) ◽  
pp. 451-453 ◽  
Author(s):  
E. Falistocco ◽  
M. Falcinelli ◽  
F. Veronesi
Keyword(s):  
Medicago Sativa ◽  
Banding Pattern ◽  
Mitotic Chromosomes ◽  
C Banding ◽  
Medicago Sativa L

scholarly journals Distribution of protein sulphydryls and disulphides in fixed mammalian chromosomes, and their relationship to banding

1984 ◽  
Vol 70 (1) ◽  
pp. 177-188
Author(s):  
A.T. Sumner
Keyword(s):  
Cross Linking ◽  
Inhomogeneous Distribution ◽  
Mitotic Chromosomes ◽  
Chromosomal Proteins ◽  
C Banding ◽  
Sulphydryl Groups ◽  
Chromosome Bands

Fixed mammalian mitotic chromosomes, when stained with a variety of sensitive, sulphydryl-specific fluorochromes directly or following reduction of disulphide groups, show uniform fluorescence. Thus sulphydryl and disulphide groups are uniformly distributed along the length of the chromosomes, and do not show patterns related to chromosome bands. Performance of G- or C-banding procedures oxidizes sulphydryls to disulphides, but does not produce an inhomogeneous distribution of these groups. Cross-linking sulphydryl groups has no effect on G-, C- or Q-banding of chromosomes. Thus there appears to be no connection between chromosome bands and the distribution or state of oxidation of sulphur in chromosomal proteins.

scholarly journals CHROMOSOME MARKERS IN MUS MUSCULUS: STRAIN DIFFERENCES IN C-BANDING

Genetics ◽  
1973 ◽  
Vol 75 (4) ◽  
pp. 663-670
Author(s):  
V G Dev ◽  
D A Miller ◽  
O J Miller
Keyword(s):  
Mus Musculus ◽  
Strain Differences ◽  
Inbred Strains ◽  
F1 Hybrids ◽  
Centromeric Heterochromatin ◽  
Mitotic Chromosomes ◽  
Homologous Chromosomes ◽  
Chromosome Markers ◽  
C Banding ◽  
Inbred Strains Of Mice

ABSTRACT The mitotic chromosomes of several inbred strains of mice and a series of F1 hybrids have been analyzed by quinacrine staining and further characterized by the centromeric heterochromatin banding (C-banding). Inbred strains had the same amount of C-banding material on homologous chromosomes but showed variation in the amount on different chromosomes. F1 hybrids showed characteristics of each parent and it appears that the amount of C-banding on each chromosome is a simple inherited polymorphism. In this study 12 different chromosomes could be distinguished by their C-banding, and these can be used as normal chromosome markers.

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