Karyotypes and Meiosis of the Morabine Grasshoppers Ii. The Genera Culmacris and Stiletta.

1979 ◽  
Vol 27 (1) ◽  
pp. 109 ◽  
Author(s):  
MJD White
Keyword(s):  
Chromosome Number ◽  
Sex Chromosome ◽  
Size And Shape ◽  
Y Chromosomes

The genus Culmacris contains no species having the primitive XO:XX sex chromosome mechanism, as found in the tribe Morabini. Two of its species have an XY:XX sex-chromosome mechanism, due to the acquisition of an X-autosome fusion (F18) early in the phylogeny of the genus. It also includes a number of taxa with X1X2Y:X1X1X2X2 sex-chromosome systems. It is proposed that this condition arose from the XY:XX one as a result of a single Y-autosome fusion (F19). The species and races of the X1X2Y section of the genus differ from one another karyotypically in respect of the size and shape of the X2 and Y chromosomes, which are especially variable; in some of them the CD autosome has undergone dissociation into separate C and D acrocentrics (D5, D7 and D8) and in one taxon the AB has also undergone dissociation (D6). This extensive karyotypic diversification contrasts with the relative morphological uniformity of this complex. The genus Stiletta contains two species with the primitive XO:XX mechanism. Both of these have a fusion between two small autosomes (F8), and one of them has an additional fusion between small autosomes (F9), giving rise to 2n = 13, the lowest chromosome number known in the Morabinae.

Y Chromosomes in Male Psychiatric Patients above 180 cm. Tall

1968 ◽  
Vol 114 (517) ◽  
pp. 1589-1590 ◽  
Author(s):  
Johannes Nielsen
Keyword(s):  
Chromosome Number ◽  
State Hospital ◽  
Psychiatric Patients ◽  
Chromosome Analysis ◽  
Y Chromosomes ◽  
Sex Chromatin ◽  
Male Patients

All male patients above 180 cm. tall who were resident in the Århus State Hospital on 13 April, 1966, were registered: they numbered 42 out of the total of 440 resident males (8 · 1 per cent.). One patient, a 78-year-old man, died before chromosome analysis was made. Sex-chromatin analysis was made on Feulgenstained buccal smears and chromosome analysis was made on leucocyte cultures according to the method described by Moorhead et al. (1960), slightly modified. Not less than 25 metaphases were counted, at least 15 metaphases with the modal figure and all metaphases with a chromosome number deviating from the modal figures were analysed.

scholarly journals Telomere-to-telomere assembly of a fish Y chromosome reveals the origin of a young sex chromosome pair

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lingzhan Xue ◽  
Yu Gao ◽  
Meiying Wu ◽  
Tian Tian ◽  
Haiping Fan ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Structural Variations ◽  
Recombination Suppression ◽  
Chromosome Differentiation ◽  
Y Chromosomes ◽  
Recent Origin ◽  
Mastacembelus Armatus

Abstract Background The origin of sex chromosomes requires the establishment of recombination suppression between the proto-sex chromosomes. In many fish species, the sex chromosome pair is homomorphic with a recent origin, providing species for studying how and why recombination suppression evolved in the initial stages of sex chromosome differentiation, but this requires accurate sequence assembly of the X and Y (or Z and W) chromosomes, which may be difficult if they are recently diverged. Results Here we produce a haplotype-resolved genome assembly of zig-zag eel (Mastacembelus armatus), an aquaculture fish, at the chromosomal scale. The diploid assembly is nearly gap-free, and in most chromosomes, we resolve the centromeric and subtelomeric heterochromatic sequences. In particular, the Y chromosome, including its highly repetitive short arm, has zero gaps. Using resequencing data, we identify a ~7 Mb fully sex-linked region (SLR), spanning the sex chromosome centromere and almost entirely embedded in the pericentromeric heterochromatin. The SLRs on the X and Y chromosomes are almost identical in sequence and gene content, but both are repetitive and heterochromatic, consistent with zero or low recombination. We further identify an HMG-domain containing gene HMGN6 in the SLR as a candidate sex-determining gene that is expressed at the onset of testis development. Conclusions Our study supports the idea that preexisting regions of low recombination, such as pericentromeric regions, can give rise to SLR in the absence of structural variations between the proto-sex chromosomes.

scholarly journals Differences in recombination frequencies during female and male meioses of the sex chromosomes of the medaka, Oryzias latipes

2001 ◽  
Vol 78 (1) ◽  
pp. 23-30 ◽  
Author(s):  
MARIKO KONDO ◽  
ERIKO NAGAO ◽  
HIROSHI MITANI ◽  
AKIHIRO SHIMA
Keyword(s):  
Genetic Map ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Oryzias Latipes ◽  
Male Recombination ◽  
Male And Female ◽  
Y Chromosomes ◽  
Genetic Length ◽  
Expressed Sequence ◽  
Group 1

In the medaka, Oryzias latipes, sex is determined chromosomally. The sex chromosomes differ from those of mammals in that the X and Y chromosomes are highly homologous. Using backcross panels for linkage analysis, we mapped 21 sequence tagged site (STS) markers on the sex chromosomes (linkage group 1). The genetic map of the sex chromosome was established using male and female meioses. The genetic length of the sex chromosome was shorter in male than in female meioses. The region where male recombination is suppressed is the region close to the sex-determining gene y, while female recombination was suppressed in both the telomeric regions. The restriction in recombination does not occur uniformly on the sex chromosome, as the genetic map distances of the markers are not proportional in male and female recombination. Thus, this observation seems to support the hypothesis that the heterogeneous sex chromosomes were derived from suppression of recombination between autosomal chromosomes. In two of the markers, Yc-2 and Casp6, which were expressed sequence-tagged (EST) sites, polymorphisms of both X and Y chromosomes were detected. The alleles of the X and Y chromosomes were also detected in O. curvinotus, a species related to the medaka. These markers could be used for genotyping the sex chromosomes in the medaka and other species, and could be used in other studies on sex chromosomes.

Fire-Setting Behavior in Individuals With Klinefelter Syndrome

PEDIATRICS ◽  
1988 ◽  
Vol 82 (1) ◽  
pp. 115-117
Author(s):  
MARVIN E. MILLER ◽  
STEPHEN SULKES
Keyword(s):  
Criminal Behavior ◽  
Sex Chromosome ◽  
Klinefelter Syndrome ◽  
Mental Deficiency ◽  
The Other ◽  
Sexual Deviation ◽  
Reactive Depression ◽  
Y Chromosomes ◽  
Psychiatric Problems ◽  
Chromosome Disorder

Klinefelter syndrome is a sex chromosome disorder with an incidence of approximately two per 1,000 male newborns.1 Eighty percent of individuals with Klinefelter syndrome are 47,XXY, whereas the other 20% have a variant sex chromosomal constitution with additional supernumerary X or Y chromosomes (ie, 48,XXXY, 48XXYY) or are mosaic.2 Individuals with Klinefelter syndrome have small testes which usually cannot produce sperm or normal amounts of testosterone. The results of this are infertility and undermasculinization. Behavioral and psychiatric problems are also common in individuals with Klinefelter syndrome and include personality disorder, reactive depression, schizophrenia, mental deficiency, sexual deviation, criminal behavior, and alcoholism.3

The Continuum of Psychosis and Its Genetic Origins

1990 ◽  
Vol 156 (6) ◽  
pp. 788-797 ◽  
Author(s):  
T. J. Crow
Keyword(s):  
Sex Chromosome ◽  
Homo Sapiens ◽  
Polymorphic Marker ◽  
Cerebral Dominance ◽  
Homo Erectus ◽  
Evolutionary Development ◽  
Pseudoautosomal Region ◽  
Sibling Pairs ◽  
Homo Habilis ◽  
Y Chromosomes

Attempts to draw a line of genetic demarcation between schizophrenic and affective illnesses have failed. It must be assumed that these diseases are genetically related. A post-mortem study has demonstrated that enlargement of the temporal horn of the lateral ventricle in schizophrenia but not in Alzheimer-type dementia is selective to the left side of the brain. This suggests that the gene for psychosis is the ‘cerebral dominance gene‘, the factor that determines the asymmetrical development of the human brain. That the psychosis gene is located in the pseudoautosomal region of the sex chromosomes is consistent with observations that sibling pairs with schizophrenia are more often than would be expected of the same sex and share alleles of a polymorphic marker at the short-arm telomeres of the X and Y chromosomes above chance expectation. That the cerebral dominance gene also is pseudoautosomal is suggested by the pattern of verbal and performance deficits associated with sex-chromosome aneuploidies. The psychoses may thus represent aberrations of a late evolutionary development underlying the recent and rapid increase in brain weight in the transition fromAustralopithecusthroughHomo habilisandHomo erectustoHomo sapiens.

scholarly journals Karyotypes of three species of Hyperophora Brunner von Wattenwyl, 1878 (Tettigoniidae, Phaneropterinae) enable morphologically similar species to be distinguished

2019 ◽  
Vol 13 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Bruno Cansanção Silva ◽  
Lucas Henrique Bonfim Souza ◽  
Juliana Chamorro-Rengifo ◽  
Douglas Araujo
Keyword(s):  
Chromosome Number ◽  
Diploid Number ◽  
Sex Chromosome ◽  
Acrocentric Chromosome ◽  
Chromosome Morphology ◽  
Similar Species ◽  
Cerrado Biome ◽  
Cytogenetic Studies ◽  
Sex Chromosome System ◽  
The Difference

Phaneropterinae is the largest subfamily of Tettigoniidae, distributed across the globe. There are few cytogenetic studies regarding this group, as in the case of the genus group Aniarae, which represents only two karyotyped species. The current study aims to analyze cytogenetically three species of Hyperophora Brunner von Wattenwyl, 1878 from Brazil. The male diploid number of Hyperophoraminor Brunner von Wattenwyl, 1891 and Hyperophoramajor Brunner von Wattenwyl, 1878 is 2n♂= 31, whereas Hyperophorabrasiliensis Brunner von Wattenwyl, 1878 has shown 2n♂= 29. These three species possess an X0 sex chromosome system and telo/acrocentric chromosome morphology. The only species found in the Pantanal biome, H.brasiliensis, can be chromosomally distinguished from the Cerrado biome species H.major and H.minor, due to the difference in chromosome number (2n♂= 29 and 2n♂= 31, respectively).

scholarly journals A new Roncus species (Pseudoscorpiones: Neobisiidae) from Montseny Natural Park (Catalonia, Spain), with remarks on karyology

Zootaxa ◽  
2008 ◽  
Vol 1693 (1) ◽  
pp. 27 ◽  
Author(s):  
JUAN A. ZARAGOZA ◽  
FRANTI“EK ŠÿÁHLAVSKÝ
Keyword(s):  
New Species ◽  
Diploid Number ◽  
Sex Chromosome ◽  
Natural Park ◽  
Y Chromosomes ◽  
Sex Chromosome System ◽  
Acrocentric Chromosomes

Roncus montsenyensis sp. nov. is described from Montseny Natural Park (Catalonia, Spain). The new species is geographically and morphologically close to Roncus cadinensis Zaragoza, 2007, but can be separated from it by palpal morphometrics, the chelal microsetae pattern and karyology. The diploid number was found to be 2n=16 in R. montsenyensis, with only biarmed chromosomes. The diploid number was found to be 2n=38 in R. cadinensis, with a predominance of acrocentric chromosomes. Both species possess the XY sex chromosome system and the X and Y chromosomes are only weakly differentiated.

Polymorphism and differentiation of rainbow trout Y chromosomes

Genome ◽  
2004 ◽  
Vol 47 (6) ◽  
pp. 1105-1113 ◽  
Author(s):  
Alicia Felip ◽  
Atushi Fujiwara ◽  
William P Young ◽  
Paul A Wheeler ◽  
Marc Noakes ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Morphological Differentiation ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Y Chromosomes ◽  
Cytogenetic Analyses ◽  
Clonal Lines ◽  
Sex Locus

Most fish species show little morphological differentiation in the sex chromosomes. We have coupled molecular and cytogenetic analyses to characterize the male-determining region of the rainbow trout (Oncorhynchus mykiss) Y chromosome. Four genetically diverse male clonal lines of this species were used for genetic and physical mapping of regions in the vicinity of the sex locus. Five markers were genetically mapped to the Y chromosome in these male lines, indicating that the sex locus was located on the same linkage group in each of the lines. We also confirmed the presence of a Y chromosome morphological polymorphism among these lines, with the Y chromosomes from two of the lines having the more common heteromorphic Y chromosome and two of the lines having Y chromosomes morphologically similar to the X chromosome. The fluorescence in situ hybridization (FISH) pattern of two probes linked to sex suggested that the sex locus is physically located on the long arm of the Y chromosome. Fishes appear to be an excellent group of organisms for studying sex chromosome evolution and differentiation in vertebrates because they show considerable variability in the mechanisms and (or) patterns involved in sex determination.Key words: sex chromosomes, sex markers, cytogenetics, rainbow trout, fish.

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.

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