Karyotypes, constitutive heterochromatin, and genomic DNA values in the blowfly genera Chrysomya, Lucilia, and Protophormia (Diptera: Calliphoridae)

Genome ◽  
2006 ◽  
Vol 49 (6) ◽  
pp. 584-597 ◽  
Author(s):  
Fritz-Helmut Ullerich ◽  
Michael Schöttke
Keyword(s):  
Dna Content ◽  
Sex Chromosome ◽  
Repetitive Sequences ◽  
Centromeric Heterochromatin ◽  
Large Chromosome ◽  
X Chromosomes ◽  
C Banding ◽  
Y Chromosomes ◽  
Dna Contents ◽  
Size And Morphology

The karyotypes and C-banding patterns of Chrysomya species C. marginalis, C. phaonis, C. pinguis, C. saffranea, C. megacephala (New Guinean strain), Lucilia sericata, and Protophormia terraenovae are described. All species are amphogenic and have similar chromosome complements (2n = 12), including an XY–XX sex-chromosome pair varying in size and morphology between species. Additionally, the C-banding pattern of the monogenic species Chrysomya albiceps is presented. The DNA contents of these and of further species Chrysomya rufifacies, Chrysomya varipes, and Chrysomya putoria were assessed on mitotic metaphases by Feulgen cytophotometry. The average 2C DNA value of the male genomes ranged from 1.04 pg in C. varipes to 2.31 pg in C. pinguis. The DNA content of metaphase X chromosomes varied from 0.013 pg (= 1.23% of the total genome) in C. varipes to 0.277 pg (12.20%) in L. sericata; that of Y chromosomes ranged from 0.003 pg (0.27%) in C. varipes to 0.104 pg (5.59%) in L. sericata. In most species, the corresponding 5 large chromosome pairs showed similar relative DNA contents. The data suggest that the interspecific DNA differences in most species are mainly due to quantitative variation of (repetitive) sequences lying outside the centromeric heterochromatin blocks of the large chromosomes. The results are also discussed with regard to phylogenetic relationships of some species.Key words: DNA content, C value, C banding, sex determination, genome evolution.

C-banded karyotypes of two Silene species with heteromorphic sex chromosomes

Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Aleksandra Grabowska-Joachimiak ◽  
Andrzej Joachimiak
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Silene Latifolia ◽  
Silene Dioica ◽  
Dna Amount ◽  
Metaphase Chromosomes ◽  
X Chromosomes ◽  
C Banding ◽  
Y Chromosomes ◽  
Heteromorphic Sex Chromosomes

Mitotic metaphase chromosomes of Silene latifolia (white campion) and Silene dioica (red campion) were studied and no substantial differences between the conventional karyotypes of these two species were detected. The classification of chromosomes into three distinct groups proposed for S. latifolia by Ciupercescu and colleagues was considered and discussed. Additionally, a new small satellite on the shorter arm of homobrachial chromosome 5 was found. Giemsa C-banded chromosomes of the two analysed species show many fixed and polymorphic heterochromatic bands, mainly distally and centromerically located. Our C-banding studies provided an opportunity to better characterize the sex chromosomes and some autosome types, and to detect differences between the two Silene karyotypes. It was shown that S. latifolia possesses a larger amount of polymorphic heterochromatin, especially of the centromeric type. The two Silene sex chromosomes are easily distinguishable not only by length or DNA amount differences but also by their Giemsa C-banding patterns. All Y chromosomes invariably show only one distally located band, and no other fixed or polymorphic bands on this chromosome were observed in either species. The X chromosomes possess two terminally located fixed bands, and some S. latifolia X chromosomes also have an extra-centric segment of variable length. The heterochromatin amount and distribution revealed by our Giemsa C-banding studies provide a clue to the problem of sex chromosome and karyotype evolution in these two closely related dioecious Silene species.Key words: dioecious plant, Silene dioica, Silene latifolia, karyotype, sex chromosomes, heterochromatin, C-banding.

Sex Chromosome Translocations

2018 ◽  
Author(s):  
R. J McKinlay Gardner ◽  
David J Amor
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Transcriptional Silencing ◽  
The Other ◽  
X Chromosomes ◽  
Chromosome Form ◽  
Chromosome Translocations ◽  
Y Chromosomes ◽  
Autosomal Translocation

The sex chromosomes (gonosomes) are different, and sex chromosome translocations need to be considered separately from translocations between autosomes. A sex chromosome can engage in translocation with an autosome, with the other sex chromosome, or even with its homolog. The qualities of the sex chromosomes have unique implications in terms of the genetic functioning of gonosome-autosome translocations. This chapter acknowledges the specific peculiarities that the sex chromosomes imply: the X being subject to transcriptional silencing; and the very small Y gene complement being confined largely to sex-determining loci. It reviews translocations between sex chromosomes and autosomes; between X and Y chromosomes; and even the very rare circumstance of between X chromosomes and between Y chromosomes. The differences in assessing risk, according to chromosome form, in comparison with the autosomal translocation, are reviewed, and the biology behind these differences is discussed.

scholarly journals Amplified Fragments of an Autosome-Borne Gene Constitute a Significant Component of the W Sex Chromosome of Eremias velox (Reptilia, Lacertidae)

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 779
Author(s):  
Artem Lisachov ◽  
Daria Andreyushkova ◽  
Guzel Davletshina ◽  
Dmitry Prokopov ◽  
Svetlana Romanenko ◽  
...  
Keyword(s):  
Sex Chromosome ◽  
De Novo ◽  
Unknown Origin ◽  
Protein Product ◽  
W Chromosome ◽  
Protein Coding ◽  
X Chromosomes ◽  
Y Chromosomes ◽  
Total Female ◽  
Evolutionary Trajectories

Heteromorphic W and Y sex chromosomes often experience gene loss and heterochromatinization, which is frequently viewed as their “degeneration”. However, the evolutionary trajectories of the heterochromosomes are in fact more complex since they may not only lose but also acquire new sequences. Previously, we found that the heterochromatic W chromosome of a lizard Eremias velox (Lacertidae) is decondensed and thus transcriptionally active during the lampbrush stage. To determine possible sources of this transcription, we sequenced DNA from a microdissected W chromosome sample and a total female DNA sample and analyzed the results of reference-based and de novo assembly. We found a new repetitive sequence, consisting of fragments of an autosomal protein-coding gene ATF7IP2, several SINE elements, and sequences of unknown origin. This repetitive element is distributed across the whole length of the W chromosome, except the centromeric region. Since it retained only 3 out of 10 original ATF7IP2 exons, it remains unclear whether it is able to produce a protein product. Subsequent studies are required to test the presence of this element in other species of Lacertidae and possible functionality. Our results provide further evidence for the view of W and Y chromosomes as not just “degraded” copies of Z and X chromosomes but independent genomic segments in which novel genetic elements may arise.

Mixed-Up Sex Chromosomes: Identification of Sex Chromosomes in the X1X1X2X2/X1X2Y System of the Legless Lizards of the Genus Lialis (Squamata: Gekkota: Pygopodidae)

2016 ◽  
Vol 149 (4) ◽  
pp. 282-289 ◽  
Author(s):  
Michail Rovatsos ◽  
Martina Johnson Pokorná ◽  
Marie Altmanová ◽  
Lukáš Kratochvíl
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Comparative Genomic ◽  
X Chromosomes ◽  
Telomeric Sequences ◽  
Multiple Sex Chromosomes ◽  
Y Chromosomes ◽  
Heteromorphic Sex Chromosomes ◽  
Cytogenetic Analyses ◽  
Male Heterogamety

Geckos in general show extensive variability in sex determining systems, but only male heterogamety has been demonstrated in the members of their legless family Pygopodidae. In the pioneering study published more than 45 years ago, multiple sex chromosomes of the type X1X1X2X2/X1X2Y were described in Burton's legless lizard (Lialisburtonis) based on conventional cytogenetic techniques. We conducted cytogenetic analyses including comparative genomic hybridization and fluorescence in situ hybridization (FISH) with selected cytogenetic markers in this species and the previously cytogenetically unstudied Papua snake lizard (Lialis jicari) to better understand the nature of these sex chromosomes and their differentiation. Both species possess male heterogamety with an X1X1X2X2/X1X2Y sex chromosome system; however, the Y and one of the X chromosomes are not small chromosomes as previously reported in L. burtonis, but the largest macrochromosomal pair in the karyotype. The Y chromosomes in both species have large heterochromatic blocks with extensive accumulations of GATA and AC microsatellite motifs. FISH with telomeric probe revealed an exclusively terminal position of telomeric sequences in L. jicari (2n = 42 chromosomes in females), but extensive interstitial signals, potentially remnants of chromosomal fusions, in L.burtonis (2n = 34 in females). Our study shows that even largely differentiated and heteromorphic sex chromosomes might be misidentified by conventional cytogenetic analyses and that the application of more sensitive cytogenetic techniques for the identification of sex chromosomes is beneficial even in the classical examples of multiple sex chromosomes.

Analysis of SINE and LINE repeat content of Y chromosomes in the platypus, Ornithorhynchus anatinus

2009 ◽  
Vol 21 (8) ◽  
pp. 964 ◽  
Author(s):  
R. Daniel Kortschak ◽  
Enkhjargal Tsend-Ayush ◽  
Frank Grützner
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Activity Patterns ◽  
Specific Sequence ◽  
X Chromosomes ◽  
Repeat Content ◽  
Y Chromosomes ◽  
Ornithorhynchus Anatinus ◽  
History Of ◽  
Sex Chromosome System

Monotremes feature an extraordinary sex-chromosome system that consists of five X and five Y chromosomes in males. These sex chromosomes share homology with bird sex chromosomes but no homology with the therian X. The genome of a female platypus was recently completed, providing unique insights into sequence and gene content of autosomes and X chromosomes, but no Y-specific sequence has so far been analysed. Here we report the isolation, sequencing and analysis of ~700 kb of sequence of the non-recombining regions of Y2, Y3 and Y5, which revealed differences in base composition and repeat content between autosomes and sex chromosomes, and within the sex chromosomes themselves. This provides the first insights into repeat content of Y chromosomes in platypus, which overall show similar patterns of repeat composition to Y chromosomes in other species. Interestingly, we also observed differences between the various Y chromosomes, and in combination with timing and activity patterns we provide an approach that can be used to examine the evolutionary history of the platypus sex-chromosome chain.

scholarly journals Sequence Differentiation Associated With an Inversion on the Neo-X Chromosome of Drosophila americana

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1317-1328 ◽  
Author(s):  
Bryant F McAllister
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Geographic Region ◽  
Sex Chromosome Evolution ◽  
Sequence Analyses ◽  
X Chromosomes ◽  
Y Chromosomes ◽  
Chromosomal Pair

Abstract Sex chromosomes originate from pairs of autosomes that acquire controlling genes in the sex-determining cascade. Universal mechanisms apparently influence the evolution of sex chromosomes, because this chromosomal pair is characteristically heteromorphic in a broad range of organisms. To examine the pattern of initial differentiation between sex chromosomes, sequence analyses were performed on a pair of newly formed sex chromosomes in Drosophila americana. This species has neo-sex chromosomes as a result of a centromeric fusion between the X chromosome and an autosome. Sequences were analyzed from the Alcohol dehydrogenase (Adh), big brain (bib), and timeless (tim) gene regions, which represent separate positions along this pair of neo-sex chromosomes. In the northwestern range of the species, the bib and Adh regions exhibit significant sequence differentiation for neo-X chromosomes relative to neo-Y chromosomes from the same geographic region and other chromosomal populations of D. americana. Furthermore, a nucleotide site defining a common haplotype in bib is shown to be associated with a paracentric inversion [In(4)ab] on the neo-X chromosome, and this inversion suppresses recombination between neo-X and neo-Y chromosomes. These observations are consistent with the inversion acting as a recombination modifier that suppresses exchange between these neo-sex chromosomes, as predicted by models of sex chromosome evolution.

scholarly journals Cognitive, Affective Problems and Renal Cross Ectopy in a Patient with 48,XXYY/47,XYY Syndrome

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Sefa Resim ◽  
Faruk Kucukdurmaz ◽  
Nazım Kankılıc ◽  
Ozlem Altunoren ◽  
Erkan Efe ◽  
...  
Keyword(s):  
Sex Chromosome ◽  
Klinefelter Syndrome ◽  
Semen Analysis ◽  
Genetic Diagnosis ◽  
Psychomotor Retardation ◽  
Tall Stature ◽  
X Chromosomes ◽  
Y Chromosomes ◽  
The Right ◽  
Hormonal Evaluation

Klinefelter syndrome is the most common sex chromosome abnormality (SCA) in infertile patients and 47,XXY genomic configuration constitutes most of the cases. However, additional Xs and/or Y such as 48,XXYY, 48,XXXY, and 47,XYY can occur less frequently than 47,XXY. Those configurations were considered as variants of Klinefelter syndrome. In this report, we present an infertile man with tall stature and decreased testicular volume. Semen analysis and hormonal evaluation supported the diagnosis of nonobstructive azoospermia. Genetic investigation demonstrated an abnormal male karyotype with two X chromosomes and two Y chromosomes consistent with 48,XXYY(17)/47,XYY (13). Additionally, the patient expressed cognitive and affective problems which were documented by psychomotor retardation and borderline intelligence measured by an IQ value between 70 and 80. Systemic evaluation also revealed cross ectopy and malrotation of the right kidney in the patient. The couple was referred to microtesticular sperm extraction (micro-TESE)/intracytoplasmic sperm injection (ICSI) cycles and preimplantation genetic diagnosis (PGD). To the best of our knowledge, this is the first report of combination of XYY and XXYY syndromes associated with cognitive, affective dysfunction and renal malrotation.

scholarly journals Phonemic and Semantic Verbal Fluency in Sex Chromosome Aneuploidy: Contrasting the Effects of Supernumerary X versus Y Chromosomes on Performance

2018 ◽  
Vol 24 (9) ◽  
pp. 917-927
Author(s):  
Manisha Udhnani ◽  
Moshe Maiman ◽  
Jonathan D. Blumenthal ◽  
Liv S. Clasen ◽  
Gregory L. Wallace ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Verbal Fluency ◽  
Maternal Education ◽  
Sex Chromosome ◽  
Past Research ◽  
Semantic Fluency ◽  
X Chromosomes ◽  
Verbal Fluency Task ◽  
Y Chromosomes ◽  
Phonemic Fluency

AbstractObjectives: Past research suggests that youth with sex chromosome aneuploidies (SCAs) present with verbal fluency deficits. However, most studies have focused on sex chromosome trisomies. Far less is known about sex chromosome tetrasomies and pentasomies. Thus, the current research sought to characterize verbal fluency performance among youth with sex chromosome trisomies, tetrasomies, and pentasomies by contrasting how performance varies as a function of extra X number and X versus Y status. Methods: Participants included 79 youth with SCAs and 42 typically developing controls matched on age, maternal education, and racial/ethnic background. Participants completed the phonemic and semantic conditions of a verbal fluency task and an abbreviated intelligence test. Results: Both supernumerary X and Y chromosomes were associated with verbal fluency deficits relative to controls. These impairments increased as a function of the number of extra X chromosomes, and the pattern of impairments on phonemic and semantic fluency differed for those with a supernumerary X versus Y chromosome. Whereas one supernumerary Y chromosome was associated with similar performance across fluency conditions, one supernumerary X chromosome was associated with relatively stronger semantic than phonemic fluency skills. Conclusions: Verbal fluency skills in youth with supernumerary X and Y chromosomes are impaired relative to controls. However, the degree of impairment varies across groups and task condition. Further research into the cognitive underpinnings of verbal fluency in youth with SCAs may provide insights into their verbal fluency deficits and help guide future treatments. (JINS, 2018, 24, 917–927)

M31 and macroH2A1.2 colocalise at the pseudoautosomal region during mouse meiosis

2001 ◽  
Vol 114 (18) ◽  
pp. 3367-3375 ◽  
Author(s):  
James M. A. Turner ◽  
Paul S. Burgoyne ◽  
Prim B. Singh
Keyword(s):  
Meiotic Prophase ◽  
Sex Chromosome ◽  
Centromeric Heterochromatin ◽  
Pseudoautosomal Region ◽  
Male And Female ◽  
Female Mice ◽  
Steroid Sulphatase ◽  
Meiotic Sex Chromosome Inactivation ◽  
Y Chromosomes ◽  
Surface Spread

Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1β or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of meiotic centromeric heterochromatin and of the sex body, the transcriptionally inactive domain of the X and Y chromosomes. This second observation has raised the possibility that these proteins co-operate in meiotic sex chromosome inactivation. In order to investigate the roles of M31 and macroH2A1.2 in meiosis in greater detail, we have examined their localisation patterns in surface-spread meiocytes from male and female mice. Using this approach, we report that, in addition to their previous described staining patterns, both proteins localise to a focus within the portion of the pseudoautosomal region (PAR) that contains the steroid sulphatase (Sts) gene. In light of the timing of its appearance and of its behaviour in sex-chromosomally variant mice, we suggest a role for this heterochromatin focus in preventing complete desynapsis of the terminally associated X and Y chromosomes prior to anaphase I.

scholarly journals Bisection of the X chromosome disrupts the initiation of chromosome silencing during meiosis in Caenorhabditis elegans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yisrael Rappaport ◽  
Hanna Achache ◽  
Roni Falk ◽  
Omer Murik ◽  
Oren Ram ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rna Polymerase Ii ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Transcription Analysis ◽  
X Chromosomes ◽  
Unique Character ◽  
Active Transcription ◽  
Heterogametic Sex

AbstractDuring meiosis, gene expression is silenced in aberrantly unsynapsed chromatin and in heterogametic sex chromosomes. Initiation of sex chromosome silencing is disrupted in meiocytes with sex chromosome-autosome translocations. To determine whether this is due to aberrant synapsis or loss of continuity of sex chromosomes, we engineered Caenorhabditis elegans nematodes with non-translocated, bisected X chromosomes. In early meiocytes of mutant males and hermaphrodites, X segments are enriched with euchromatin assembly markers and active RNA polymerase II staining, indicating active transcription. Analysis of RNA-seq data showed that genes from the X chromosome are upregulated in gonads of mutant worms. Contrary to previous models, which predicted that any unsynapsed chromatin is silenced during meiosis, our data indicate that unsynapsed X segments are transcribed. Therefore, our results suggest that sex chromosome chromatin has a unique character that facilitates its meiotic expression when its continuity is lost, regardless of whether or not it is synapsed.

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