BANDING PATTERNS IN MITOTIC CHROMOSOMES OF THE RABBIT (ORYCTOLAGUS CUNICULUS)

1977 ◽  
Vol 19 (4) ◽  
pp. 625-632 ◽  
Author(s):  
F. P. H. Chan ◽  
F. R. Sergovich ◽  
E. L. Shaver
Keyword(s):  
Detailed Analysis ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Banding Pattern ◽  
Oryctolagus Cuniculus ◽  
Acrocentric Chromosome ◽  
Mitotic Chromosomes ◽  
Banding Patterns ◽  
Medium Length

A detailed analysis of rabbit mitotic chromosomes stained with quinacrine and Trypsin-Giemsa methods to elucidate the Q and G bands is presented. Each of the 21 pairs of autosomes can be identified unequivocally. The sex chromosomes can also be distinguished from the autosomes. The X chromosome is a medium length submetacentric with its own distinctive banding pattern. The Y chromosome is the smallest acrocentric chromosome and fluoresces with a medium intensity.

Analysis of the sex chromosomes of the Mediterranean fruit fly by microdissected DNA probes

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Ute Willhoeft ◽  
Jutta Mueller-Navia ◽  
Gerald Franz
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Oligonucleotide Primer ◽  
Mitotic Chromosomes ◽  
Degenerate Oligonucleotide ◽  
The Mediterranean

In the Mediterranean fruit fly, Ceratitis capitata, the sex-determining region maps to the long arm of the Y chromosome. DNA from this region of the Y chromosome and, for comparison, from the tip of the long arm of the X chromosome, was isolated by microdissection and amplified by degenerate oligonucleotide primer PCR (DOP-PCR). FISH of the Y-chromosomal microdissection products medY1-medY5 to mitotic chromosomes revealed hybridization signals on most of the long arm of the Y chromosome, including the male-determining region, and on the long arm of the X chromosome, as well as weaker signals on the autosomes, some of which were located in the heterochromatin next to the centromeres. The X-chromosomal microdissected probe medX1 revealed strong signals on the sex chromosomes and randomly distributed signals on the autosomes. Chromosomal in situ suppression hybridization indicates that the Y chromosome contains considerable amounts of Y-enriched and Y-specific sequences and that X-enriched sequences are present on the long arm of the X chromosome. The microdissected probes medY1, medY2, and medX1 hybridize to the sex chromosomes of two closely related species,Ceratitis rosa and Trirhithrum coffeae.

THE GIEMSA BANDING PATTERN OF THE AUSTRALIAN SWAMP BUFFALO (BUBALUS BUBALIS): CHROMOSOME HOMOLOGY WITH OTHER BOVIDAE

1976 ◽  
Vol 18 (2) ◽  
pp. 303-310 ◽  
Author(s):  
G. L. Toll ◽  
C. R. E. Halnan
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Banding Pattern ◽  
Bubalus Bubalis ◽  
The Other ◽  
Giemsa Banding ◽  
Apparent Absence ◽  
Banding Patterns ◽  
Chromosome Homology ◽  
Swamp Buffalo

A Giemsa banding method was used to obtain preparations from which a G-band idiogram for the chromosomes of the Australian Swamp Buffalo (Bubalus bubalis) was constructed. Comparison with the G-banding patterns for goat, sheep, and ox chromosomes showed a remarkably close similarity between individual pairs, banding pattern homologies for the buffalo metacentric autosomes being identifiable among the acrocentric autosomes of the other species. However, the goat and sheep lacked a comparable autosome to the buffalo 10, the buffalo lacked an autosome comparable to the ox 12, the acrocentric X chromosome of the buffalo banded most closely to the goat X and was least like the ox. The buffalo Y chromosome was unlike its counterpart in the other species. The results are in keeping with the previously expressed view of evolution within the Bovidae by a Robertsonian mechanism modified by the apparent absence of one pair of autosomes from the buffalo and of a different pair from sheep and goats.

Genetic Content of the Neo-Sex Chromosomes in Ctenonotus and Norops (Squamata, Dactyloidae) and Degeneration of the Y Chromosome as Revealed by High-Throughput Sequencing of Individual Chromosomes

2019 ◽  
Vol 157 (1-2) ◽  
pp. 115-122 ◽  
Author(s):  
Artem P. Lisachov ◽  
Alexey I. Makunin ◽  
Massimo Giovannotti ◽  
Jorge C. Pereira ◽  
Anna S. Druzhkova ◽  
...  
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
High Throughput ◽  
Sex Chromosomes ◽  
High Throughput Sequencing ◽  
Anolis Carolinensis ◽  
Pseudoautosomal Region ◽  
Central Component ◽  
Similar System ◽  
Divergence Estimates

Pleurodont lizards are characterized by an ancient system of sex chromosomes. Along with stability of the central component of the system (homologous to the X chromosome of Anolis carolinensis [Dactyloidae], ACAX), in some genera the ancestral sex chromosomes are fused with microautosomes, forming neo-sex chromosomes. The genus Ctenonotus (Dactyloidae) is characterized by multiple X1X1X2X2/X1X2Y sex chromosomes. According to cytogenetic data, the large neo-Y chromosome is formed by fusion of the ancestral Y chromosome with 2 microautosomes (homologous to ACA10 or ACA11 and ACA12), the X1 chromosome is formed by fusion of the ancestral X chromosome with the autosome homologous to ACA10 or ACA11, and the X2 chromosome is homologous to autosome ACA12. To determine more precisely the content and evolution of the Ctenonotus sex chromosomes, we sequenced flow-sorted chromosomes (both sex chromosomes and microautosomes as control) of 2 species with a similar system: C. pogus and C. sabanus. Our results indicate that the translocated part of the X1 is homologous to ACA11, X2 is homologous to ACA12, and the Y contains segments homologous to both ACA11 and ACA12. Molecular divergence estimates suggest that the ancestral X-derived part has completely degenerated in the Y of Ctenonotus, similar to the degeneration of the Norops sagrei Y chromosome (Dactyloidae). The newly added regions show loss of DNA content, but without degeneration of the conserved regions. We hypothesize that the translocation of autosomal blocks onto sex chromosomes facilitated rapid degeneration of the pseudoautosomal region on the ancestral Y.

Chromosomal homology of wood bison and plains bison

1977 ◽  
Vol 55 (10) ◽  
pp. 1759-1762 ◽  
Author(s):  
K. L. Ying ◽  
D. G. Peden
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Bison Bison ◽  
Banding Patterns ◽  
X Chromosomes ◽  
Chromosomal Homology ◽  
Wood Bison

Karyotypes of wood bison (Bison bison athabascae) and plains bison (Bison bison bison) were studied. Both subspecies were characterized by the same number of chromosomes (2n = 60), acrocentric autosomes, submetacentric X chromosomes, and an acrocentric Y chromosome. G-banding patterns suggest that when comparing wood bison and plains bison, 20 pair plus the sex chromosomes are homologous. Whether or not the remaining nine pair of chromosomes are homologous remains unknown.

scholarly journals Guppy Y Chromosome Integrity Maintained by Incomplete Recombination Suppression

2020 ◽  
Vol 12 (6) ◽  
pp. 965-977 ◽  
Author(s):  
Iulia Darolti ◽  
Alison E Wright ◽  
Judith E Mank
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Poecilia Reticulata ◽  
Sex Chromosome ◽  
Rna Seq ◽  
Recombination Suppression ◽  
Sex Chromosome System ◽  
Chromosome Integrity ◽  
Heterogametic Sex

Abstract The loss of recombination triggers divergence between the sex chromosomes and promotes degeneration of the sex-limited chromosome. Several livebearers within the genus Poecilia share a male-heterogametic sex chromosome system that is roughly 20 Myr old, with extreme variation in the degree of Y chromosome divergence. In Poecilia picta, the Y is highly degenerate and associated with complete X chromosome dosage compensation. In contrast, although recombination is restricted across almost the entire length of the sex chromosomes in Poecilia reticulata and Poecilia wingei, divergence between the X chromosome and the Y chromosome is very low. This clade therefore offers a unique opportunity to study the forces that accelerate or hinder sex chromosome divergence. We used RNA-seq data from multiple families of both P. reticulata and P. wingei, the species with low levels of sex chromosome divergence, to differentiate X and Y coding sequences based on sex-limited SNP inheritance. Phylogenetic tree analyses reveal that occasional recombination has persisted between the sex chromosomes for much of their length, as X- and Y-linked sequences cluster by species instead of by gametolog. This incomplete recombination suppression maintains the extensive homomorphy observed in these systems. In addition, we see differences between the previously identified strata in the phylogenetic clustering of X–Y orthologs, with those that cluster by chromosome located in the older stratum, the region previously associated with the sex-determining locus. However, recombination arrest appears to have expanded throughout the sex chromosomes more gradually instead of through a stepwise process associated with inversions.

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.

scholarly journals The Effect of Hybridization on Dosage Compensation in Member Species of the Anopheles gambiae Species Complex

2018 ◽  
Author(s):  
Kevin C. Deitz ◽  
Willem Takken ◽  
Michel A. Slotman
Keyword(s):  
Sex Determination ◽  
Anopheles Gambiae ◽  
Y Chromosome ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Species Complex ◽  
F1 Hybrids ◽  
Chromosome Gene ◽  
Heterogametic Sex

AbstractDosage compensation has evolved in concert with Y-chromosome degeneration in many taxa that exhibit heterogametic sex chromosomes. Dosage compensation overcomes the biological challenge of a "half dose" of X chromosome gene transcripts in the heterogametic sex. The need to equalize gene expression of a hemizygous X with that of autosomes arises from the fact that the X chromosomes retain hundreds of functional genes that are actively transcribed in both sexes and interact with genes expressed on the autosomes. Sex determination and heterogametic sex chromosomes have evolved multiple times in Diptera, and in each case the genetic control of dosage compensation is tightly linked to sex determination. In the Anopheles gambiae species complex (Culicidae), maleness is conferred by the Y-chromosome gene Yob, which despite its conserved role between species is polymorphic in its copy number between them. Previous work demonstrated that male An. gambiae s.s. males exhibit complete dosage compensation in pupal and adult stages. In the present study we have extended this analysis to three sister species in the An. gambiae complex: An. coluzzii, An. arabiensis, and An. quadriannulatus. In addition, we analyzed dosage compensation in bi-directional F1 hybrids between these species to determine if hybridization results in the mis-regulation and disruption of dosage compensation. Our results confirm that dosage compensation operates in the An. gambiae species complex through the hyper-transcription of the male X chromosome. Additionally, dosage compensation in hybrid males does not differ from parental males, indicating that hybridization does not result in the mis-regulation of dosage compensation.

The Chromosomes of Six Species of the Drosophila lativittata Complex

1984 ◽  
Vol 32 (1) ◽  
pp. 43 ◽  
Author(s):  
IR Bock
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Sexual Isolation ◽  
Species Group ◽  
Interspecific Crosses ◽  
Banding Patterns ◽  
Australian Species

Metaphase and polytene karyotypes were investigated in six Australian species of the Drosophila (Scaptodrosophila) coracina species-group: lativittata, enigma, specensis, howensis, nitidithorax and novamaculosa. The male metaphase karyotype of each species consists of three pairs of telocentric; one pair of metacentric and one pair of small heterochromatic chromosomes, plus a large acrocentric X-chromosome and a smaller acrocentric Y-chromosome. The polytene karyotype of each species consists of six arms and a small chromocentre. No inversion polymorphisms were found in the two species (lativittata and enigma) investigated for this phenomenon. Interspecific crosses obtained between enigma and howensis and between lativittata and nitidithorax revealed that the former species (between which sexual isolation is incomplete) are entirely homosequential, and differences in polytene banding patterns between the latter species are very slight. Photographic comparisons otherwise revealed that the banding sequences of all six species are substantially identical.

Chromosomes of Onchocerca volvulus (Spirurida:Onchocercidae): A comparative study between Nigeria and Guatemala

1987 ◽  
Vol 61 (1) ◽  
pp. 43-46 ◽  
Author(s):  
H. Hirai ◽  
I. Tada ◽  
H. Takahashi ◽  
B. E. B. Nwoke ◽  
G. O. Ufomadu
Keyword(s):  
Comparative Study ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Onchocerca Volvulus

ABSTRACTChromosomes of Nigerian Onchocerca volvulus were compared with those of Guatemalan O. volvulus. Both parasites had basically the same chromosomal construct (2n=8, XY type). Autosomes consisted of a pair of large and two smaller pairs. Sex chromosomes were made up of medium sized X chromosome and very small Y chromosome. It was not possible to infer the position of the centromeres.

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