On the cytology of two species of Necrobia (Oliv.) (Coleoptera: Cleridae)

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 165-167 ◽  
Author(s):  
J. S. Yadav ◽  
M. P. Dange
Keyword(s):  
Cell Division ◽  
Pericentric Inversion ◽  
Sex Chromosome ◽  
Evolution Of Karyotypes ◽  
Male Karyotype

The karyology of Necrobia ruficollis F. and Necrobia rufipes De Geer was investigated. The male karyotype of the species is 18♀:8+Xyp. Details of structure and behaviour of chromosomes during cell division are presented. Variations in the morphology of chromosomes in Necrobia species and trends in the evolution of karyotypes in the Cleridae are discussed.Key words: Cleridae, karyotype, sex chromosome mechanism, polyphaga, pericentric inversion.

scholarly journals Chromosomal Evolution in the Lizard Genus Varanus (Reptilia)

1975 ◽  
Vol 28 (1) ◽  
pp. 89 ◽  
Author(s):  
Max Kinga ◽  
Dennis King
Keyword(s):  
Chromosome Number ◽  
Pericentric Inversion ◽  
Sex Chromosome ◽  
Chromosomal Rearrangements ◽  
Chromosomal Evolution ◽  
Size Groups ◽  
Sex Chromosome System

The karyotypes have been determined of 16 of the 32 species of the genus Varanus, including animals from Africa, Israel, Malaya and Australia. A constant chromosome number of 2n = 40 was observed. The karyotype is divided into eight pairs of large chromosomes and 12 pairs of microchromosomes. A series of chromosomal rearrangements have become established in both size groups of the karyotype and are restricted to centromere shifts, probably caused by pericentric inversion. Species could be placed in one of six distinct karyotype groups which are differentiated by these rearrangements and whose grouping does not always correspond with the current taxonomy. An unusual sex chromosome system of the ZZjZW type was present in a number of the species examined.

scholarly journals Identification of sex chromosomes using genomic and cytogenetic methods in a range-expanding spider, Argiope bruennichi (Araneae: Araneidae)

2021 ◽  
Author(s):  
Monica M Sheffer ◽  
Mathilde M Cordellier ◽  
Martin Forman ◽  
Malte Grewoldt ◽  
Katharina Hoffmann ◽  
...  
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Chromosome Complement ◽  
Gc Content ◽  
Sexually Dimorphic ◽  
Behavioral Experiments ◽  
X Chromosomes ◽  
Male Karyotype ◽  
And Behavior

Differences between sexes in growth, ecology and behavior strongly shape species biology. In some animal groups, such as spiders, it is difficult or impossible to identify the sex of juveniles. This information would be useful for field surveys, behavioral experiments, and ecological studies on e.g. sex ratios and dispersal. In species with sex chromosomes, sex can be determined based on the specific sex chromosome complement. Additionally, information on the sequence of sex chromosomes provides the basis for studying sex chromosome evolution. We combined cytogenetic and genomic data to identify the sex chromosomes in the sexually dimorphic spider Argiope bruennichi, and designed RT-qPCR sex markers. We found that genome size and GC content of this spider falls into the range reported for the majority of araneids. The male karyotype is formed by 24 acrocentric chromosomes with an X1X20 sex chromosome system, with little similarity between X chromosomes, suggesting origin of these chromosomes by X chromosome fission or early duplication of an X chromosome and subsequent independent differentiation of the copies. Our data suggest similarly sized X chromosomes in A. bruennichi. They are smaller chromosomes of the complement. Our findings open the door to new directions in spider evolutionary and ecological research.

Robertsonian Fusion, Pericentric Inversion and Sex Chromosome Heteromorphisms inOryzomys Subflavus(Cricetidae, Rodentia)

Caryologia ◽  
1985 ◽  
Vol 38 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eunice Judith Cardoso De Almeida ◽  
Yatiyo Yonenaga-Yassuda
Keyword(s):  
Pericentric Inversion ◽  
Sex Chromosome ◽  
Robertsonian Fusion

scholarly journals Repetitive centromeric satellite RNA is essential for kinetochore formation and cell division

2014 ◽  
Vol 207 (3) ◽  
pp. 335-349 ◽  
Author(s):  
Silvana Rošić ◽  
Florian Köhler ◽  
Sylvia Erhardt
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Noncoding Rna ◽  
Genome Stability ◽  
Sex Chromosome ◽  
Epigenetic Mark ◽  
Epigenetic Mechanisms ◽  
Satellite Rna ◽  
Centromeric Dna ◽  
In Trans

Chromosome segregation requires centromeres on every sister chromatid to correctly form and attach the microtubule spindle during cell division. Even though centromeres are essential for genome stability, the underlying centromeric DNA is highly variable in sequence and evolves quickly. Epigenetic mechanisms are therefore thought to regulate centromeres. Here, we show that the 359-bp repeat satellite III (SAT III), which spans megabases on the X chromosome of Drosophila melanogaster, produces a long noncoding RNA that localizes to centromeric regions of all major chromosomes. Depletion of SAT III RNA causes mitotic defects, not only of the sex chromosome but also in trans of all autosomes. We furthermore find that SAT III RNA binds to the kinetochore component CENP-C, and is required for correct localization of the centromere-defining proteins CENP-A and CENP-C, as well as outer kinetochore proteins. In conclusion, our data reveal that SAT III RNA is an integral part of centromere identity, adding RNA to the complex epigenetic mark at centromeres in flies.

scholarly journals Morphological and cytogenetic characteristics of Neobisium (Blothrus) slovacum Gulička, 1977 (Pseudoscorpiones, Neobisiidae), the northernmost troglobitic species of the subgenus Blothrus in Europe

ZooKeys ◽  
2019 ◽  
Vol 817 ◽  
pp. 113-130 ◽  
Author(s):  
Martina Červená ◽  
František Šťáhlavský ◽  
Vladimír Papáč ◽  
Ľubomír Kováč ◽  
Jana Christophoryová
Keyword(s):  
In Situ Hybridization ◽  
18S Rdna ◽  
Sex Chromosome ◽  
Karst Area ◽  
Museum Specimens ◽  
Life Stages ◽  
Sex Chromosome System ◽  
Male Karyotype ◽  
North Western

A redescription is provided of the adult, tritonymph and deutonymph life stages of the troglobitic Neobisium (Blothrus) slovacum Gulička, 1977, which is known from Slovakia and Hungary. Material examined included 35 previously deposited museum specimens and 15 newly collected specimens. In addition, the karyotype and distribution of 18S rDNA clusters are described, using fluorescence in situ hybridization (FISH). The male karyotype ofN.slovacumcomprises 69 chromosomes, with a predominance of biarmed chromosomes, and an X0 sex chromosome system. Two pairs of signals for 18S rDNA on biarmed chromosomes (submetacentric and metacentric) of different sizes were identified. The present study provides the first information about the distribution of these clusters in the arachnid order Pseudoscorpiones. The geographic distribution of the species is summarized and mapped.Neobisiumslovacumis endemic to the Slovak and Aggtelek Karst area in southern Slovakia and north-western Hungary, where it has been recorded from 16 caves. One of these, Hačavská cave (in Slovakia), is the northernmost locality known for any species of the subgenus Blothrus.

scholarly journals New evidence for the presence of the telomere motif (TTAGG) n in the family Reduviidae and its absence in the families Nabidae and Miridae (Hemiptera, Cimicomorpha)

2019 ◽  
Vol 13 (3) ◽  
pp. 283-295 ◽  
Author(s):  
Snejana Grozeva ◽  
Boris A. Anokhin ◽  
Nikolay Simov ◽  
Valentina G. Kuznetsova
Keyword(s):  
Ribosomal Dna ◽  
Sex Chromosomes ◽  
18S Rdna ◽  
Sex Chromosome ◽  
Giemsa Staining ◽  
Y Chromosomes ◽  
The Family ◽  
Male Karyotype ◽  
First Time ◽  
New Evidence

Male karyotype and meiosis in four true bug species belonging to the families Reduviidae, Nabidae, and Miridae (Cimicomorpha) were studied for the first time using Giemsa staining and FISH with 18S ribosomal DNA and telomeric (TTAGG)n probes. We found that Rhynocoris punctiventris (Herrich-Schäffer, 1846) and R. iracundus (Poda, 1761) (Reduviidae: Harpactorinae) had 2n = 28 (24 + X1X2X3Y), whereas Nabis sareptanus Dohrn, 1862 (Nabidae) and Horistus orientalis (Gmelin, 1790) (Miridae) had 2n = 34 (32 + XY) and 2n = 32 (30 + XY), respectively. FISH for 18S rDNA revealed hybridization signals on a sex chromosome, the X or the Y, in H. orientalis, on both X and Y chromosomes in N. sareptanus, and on two of the four sex chromosomes, Y and one of the Xs, in both species of Rhynocoris Hahn, 1834. The results of FISH with telomeric probes support with confidence the absence of the “insect” telomere motif (TTAGG)n in the families Nabidae and Miridae and its presence in both species of genus Rhynocoris of the Reduviidae, considered as a basal family of Cimicomorpha. Increasing evidence reinforces the hypothesis of the loss of the canonical “insect” telomere motif (TTAGG)n by at least four cimicomorphan families, Nabidae, Miridae, Tingidae, and Cimicidae, for which data are currently available.

A Challenging Prenatal QF-PCR Rapid Aneuploidy Test Result Caused by a Maternally Inherited Triplication within Chromosome Xq26.2

2018 ◽  
Vol 156 (1) ◽  
pp. 5-8
Author(s):  
Amy Inkster ◽  
Mary Ann Thomas ◽  
Nadine S. Gamache ◽  
Michael Chan ◽  
Pernilla Stenroos ◽  
...  
Keyword(s):  
Microsatellite Marker ◽  
X Chromosome ◽  
Copy Number ◽  
Sex Chromosome ◽  
Chromosome Analysis ◽  
First Trimester ◽  
Chromosomal Microarray ◽  
Normal Male ◽  
Fluorescent Polymerase Chain Reaction ◽  
Male Karyotype

The aim of this study was to investigate the origin of the biallelic trisomic amplification pattern of the X chromosome microsatellite marker DXS1187 in an otherwise normal male fetus, identified on routine rapid aneuploidy detection (RAD) testing by quantitative fluorescent-polymerase chain reaction (QF-PCR). Amniocentesis was performed on a 35-year-old female at 15 weeks, 2 days gestation for a positive first trimester screen. QF-PCR, metaphase FISH, and chromosomal microarray were carried out on both maternal and fetal DNA. Fetal QF-PCR showed a biallelic trisomic pattern for the X chromosome microsatellite marker DXS1187, with an otherwise normal male amplification pattern at all other sex chromosome markers. Chromosome analysis performed on cultured amniocytes showed a normal male karyotype. Chromosome microarray analysis identified a maternally inherited 304-kb copy number triplication within chromosome Xq26.2 encompassing the DXS1187 marker. The maternally inherited X chromosome harbors an apparently tandem 304-kb triplication that overlaps the DXS1187 marker. As the triplicated region is devoid of clinically relevant genes, it was considered as likely benign in the fetus. Postnatal follow-up reported a healthy male newborn. To our knowledge, this is a unique case demonstrating a “benign” copy number imbalance involving the DXS1187 marker detected by prenatal QF-PCR RAD.

scholarly journals Range Overlap Drives Chromosome Inversion Fixation in Passerine Birds

2016 ◽  
Author(s):  
Daniel M. Hooper
Keyword(s):  
Pericentric Inversion ◽  
Sex Chromosome ◽  
Gc Content ◽  
Divergence Times ◽  
Passerine Birds ◽  
Genomic Context ◽  
Chromosome Inversion ◽  
Closely Related Species ◽  
Chromosome Inversions ◽  
Range Overlap

Chromosome inversions evolve frequently but the reasons why remain largely enigmatic. I used cytological descriptions of 410 species of passerine birds (order Passeriformes) to identify pericentric inversion differences between species. Using a new fossil-calibrated phylogeny I examine the phylogenetic, demographic, and genomic context in which these inversions have evolved. The number of inversion differences between closely related species was highly variable yet consistently predicted by a single factor: whether the ranges of species overlapped. This observation holds even when the analysis is restricted to sympatric sister pairs known to hybridize, and which have divergence times estimated similar to allopatric pairs. Inversions were significantly more likely to have fixed on a sex chromosome than an autosome yet variable mutagenic input alone (by chromosome size, map length, GC content, or repeat density) cannot explain the differences between chromosomes in the number of inversions fixed. Together, these results support a model in which inversions in passerines are adaptive and spread by selection when gene flow occurs before reproductive isolation is complete.

The Ultrastructure of the Nuclear Events of Binary Fission in Paramecium bursaria and the Effects of Colchicine on Cell Division

1974 ◽  
Vol 32 ◽  
pp. 276-277
Author(s):  
L. M. Lewis
Keyword(s):  
Cell Division ◽  
Nuclear Envelope ◽  
Condensed Chromatin ◽  
Binary Fission ◽  
Paramecium Bursaria ◽  
Nuclear Events ◽  
Division Axis

The effects of colchicine on extranuclear microtubules associated with the macronucleus of Paramecium bursaria were studied to determine the possible role that these microtubules play in controlling the shape of the macronucleus. In the course of this study, the ultrastructure of the nuclear events of binary fission in control cells was also studied.During interphase in control cells, the micronucleus contains randomly distributed clumps of condensed chromatin and microtubular fragments. Throughout mitosis the nuclear envelope remains intact. During micronuclear prophase, cup-shaped microfilamentous structures appear that are filled with condensing chromatin. Microtubules are also present and are parallel to the division axis.

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