SRY and karyotypic status of one abnormal and two intersexual marsupials

1997 ◽  
Vol 9 (2) ◽  
pp. 233 ◽  
Author(s):  
C. M. Watson ◽  
P. G. Johnston ◽  
K. A. Rodger ◽  
L. M. McKenzie ◽  
R. J. Waugh O'Neill ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Y Chromosome ◽  
Sex Chromosome ◽  
Sex Differentiation ◽  
Sry Gene ◽  
Genetic Studies ◽  
Cultured Fibroblasts ◽  
Red Kangaroo ◽  
Grey Kangaroo ◽  
Macropus Rufus

An intersexual agile wallaby (Macropus agilis) with a penis, a pouch and four teats had a sex-chromosome constitution of XXY in lymphocytes and cultured fibroblasts; the sex-determining region Y (SRY) gene was present, consistent with the presence of a testis. An intersexual eastern grey kangaroo (Macropus giganteus) with a small empty scrotum and no penis, and an abnormal red kangaroo (Macropus rufus) with no penis, pouch or teats, both had XX sex-chromosome complements; the SRY gene was not present, consistent with testis absence. The agile wallaby and grey kangaroo described here provide further evidence that scrotal development in marsupials is independent of the Y chromosome. The cause of the abnormalities in the XX individuals cannot be determined until candidate genes are identified. These animals provide a basis for further genetic studies into marsupial intersexuality and sex differentiation.

A comparative study of macroscopic and microscopic dimensions of the intensine in five macropods (Marsupialia: Macropodidae). I. Allometric relationships.

1992 ◽  
Vol 40 (1) ◽  
pp. 91 ◽  
Author(s):  
R Osawa ◽  
PF Woodall
Keyword(s):  
Body Size ◽  
Confidence Limits ◽  
Surface Areas ◽  
Red Kangaroo ◽  
A Value ◽  
Grey Kangaroo ◽  
Macropus Rufus ◽  
Villous Height ◽  
Kleiber’S Law ◽  
Swamp Wallaby

Macroscopic and microscopic dimensions of the intestines in five macropod species (the red kangaroo, Macropus rufus; the eastern grey kangaroo, M. giganteus; the agile wallaby, M. agilis; the swamp wallaby, Wallabia bicolor; and the red-necked pademelon, Thylogale thetis) were investigated allometrically in relation to body mass. In general, the length of the small intestine changed in an area : volume (A:V) compensating manner, but the circumference showed negative allometry such that the overall change in surface areas, both ground and mucosal (including the contribution of villi), were isometric but also included the coefficient derived from 'Kleiber's Law' (0.75) in their 95 and 99% confidence limits, respectively. Villous height and width generally showed no significant correlations with body size, but villous density was lower in large individuals. The allometry coefficient for the length of the large intestine was generally near the A:V compensating value (0.5) in most intraspecific analyses but much higher in the interspecific analysis, suggesting that some factor other than body size might be important (possibly dietary fibre). Caecal length was significantly correlated with body size only in two largest species (M. rufus and M. giganteus) and the interspecific analysis gave a value near A:V compensation).

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

scholarly journals Programming of the reproductive axis by hormonal and genetic manipulation in mice

Reproduction ◽  
2018 ◽  
Author(s):  
Susana B Rulli ◽  
María Julia Cambiasso ◽  
Laura D Ratner
Keyword(s):  
Sex Chromosome ◽  
Genetic Manipulation ◽  
Sex Differentiation ◽  
Reproductive Function ◽  
Gonadal Steroids ◽  
Critical Periods ◽  
Female Reproduction ◽  
Control Male ◽  
Male And Female ◽  
The Brain

In mammals, the reproductive function is controlled by the hypothalamic-pituitary-gonadal axis. During development, mechanisms mediated by gonadal steroids exert an imprinting at the hypothalamic-pituitary level, by establishing sexual differences in the circuits that control male and female reproduction. In rodents, the testicular production of androgens increases drastically during the fetal/neonatal stage. This process is essential for the masculinization of the reproductive tract, genitals and brain. The conversion of androgens to estrogens in the brain is crucial for the male sexual differentiation and behavior. Conversely, feminization of the brain occurs in the absence of high levels of gonadal steroids during the perinatal period in females. Potential genetic contribution to the differentiation of brain cells through direct effects of genes located on sex chromosomes is also relevant. In this review, we will focus on the phenotypic alterations that occur on the hypothalamic-pituitary-gonadal axis of transgenic mice with persistently elevated expression of the human chorionic gonadotropin hormone (hCG). Excess of endogenously synthesized gonadal steroids due to a constant hCG stimulation is able to disrupt the developmental programming of the hypothalamic-pituitary axis in both transgenic males and females. Locally produced estrogens by the hypothalamic aromatase might play a key role in the phenotype of these mice. The “four core genotypes” mouse model demonstrated a potential influence of sex chromosome genes in brain masculinization before critical periods of sex differentiation. Thus, hormonal and genetic factors interact to regulate the local production of the neurosteroids necessary for the programming of the male and female reproductive function.

scholarly journals X and Y Chromosome Complement Influence Adiposity and Metabolism in Mice

Endocrinology ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 1092-1104 ◽  
Author(s):  
Xuqi Chen ◽  
Rebecca McClusky ◽  
Yuichiro Itoh ◽  
Karen Reue ◽  
Arthur P. Arnold
Keyword(s):  
Body Weight ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Chromosome Complement ◽  
Gonadal Hormones ◽  
Xy Model ◽  
Second Sex ◽  
Metabolic Variables ◽  
Novel Model

Abstract Three different models of MF1 strain mice were studied to measure the effects of gonadal secretions and sex chromosome type and number on body weight and composition, and on related metabolic variables such as glucose homeostasis, feeding, and activity. The 3 genetic models varied sex chromosome complement in different ways, as follows: 1) “four core genotypes” mice, comprising XX and XY gonadal males, and XX and XY gonadal females; 2) the XY* model comprising groups similar to XO, XX, XY, and XXY; and 3) a novel model comprising 6 groups having XO, XX, and XY chromosomes with either testes or ovaries. In gonadally intact mice, gonadal males were heavier than gonadal females, but sex chromosome complement also influenced weight. The male/female difference was abolished by adult gonadectomy, after which mice with 2 sex chromosomes (XX or XY) had greater body weight and percentage of body fat than mice with 1 X chromosome. A second sex chromosome of either type, X or Y, had similar effects, indicating that the 2 sex chromosomes each possess factors that influence body weight and composition in the MF1 genetic background. Sex chromosome complement also influenced metabolic variables such as food intake and glucose tolerance. The results reveal a role for the Y chromosome in metabolism independent of testes and gonadal hormones and point to a small number of X–Y gene pairs with similar coding sequences as candidates for causing these effects.

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.

Diagnosis and treatment of mesenteric volvulus in a red kangaroo (Macropus rufus)

2014 ◽  
Vol 244 (7) ◽  
pp. 844-850 ◽  
Author(s):  
S. Emmanuelle Knafo ◽  
Alana J. Rosenblatt ◽  
James K. Morrisey ◽  
James A. Flanders ◽  
Margret S. Thompson ◽  
...  
Keyword(s):  
Diagnosis And Treatment ◽  
Red Kangaroo ◽  
Macropus Rufus

scholarly journals A Systematic Review on Extreme Phenotype Strategies to Search for Rare Variants in Genetic Studies of Complex Disorders

2020 ◽  
Author(s):  
Sana Amanat ◽  
Teresa Requena ◽  
Jose Antonio Lopez-Escamez
Keyword(s):  
Systematic Review ◽  
Candidate Genes ◽  
Rare Variants ◽  
De Novo ◽  
Complex Diseases ◽  
De Novo Mutations ◽  
Genetic Studies ◽  
Complex Disorders ◽  
Extreme Phenotype ◽  
Age Related

Exome sequencing has been commonly used in rare diseases by selecting multiplex families or singletons with an extreme phenotype (EP) to search for rare variants in coding regions. The EP strategy covers both extreme ends of a disease spectrum and it has been also used to investigate the contribution of rare variants to heritability in complex clinical traits. We have conducted a systematic review to find evidence supporting the use of EP strategies to search for rare variants in genetic studies of complex diseases, to highlight the contribution of rare variation to the genetic structure of multiallelic conditions. After performing the quality assessment of the retrieved records, we selected 19 genetic studies considering EP to demonstrate genetic association. All the studies successfully identified several rare variants, de novo mutations and many novel candidate genes were also identified by selecting an EP. There is enough evidence to support that the EP approach in patients with an early onset of the disease can contribute to the identification of rare variants in candidate genes or pathways involved in complex diseases. EP patients may contribute to a better understanding of the underlying genetic architecture of common heterogeneous disorders such as tinnitus or age-related hearing loss.

scholarly journals Interrogation of cancer gene dependencies reveals novel paralog interactions of autosome and sex chromosome encoded genes

2021 ◽  
Author(s):  
Anna Köferle ◽  
Andreas Schlattl ◽  
Alexandra Hörmann ◽  
Fiona Spreitzer ◽  
Alexandra M. Popa ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Therapeutic Strategy ◽  
Sex Chromosome ◽  
De Novo ◽  
Chromosome Loss ◽  
Potential Candidate ◽  
Loss Of Function ◽  
Male Patients ◽  
Tumour Cell Lines ◽  
Paralog Gene

Genetic networks are characterized by extensive buffering. During tumour evolution, disruption of these functional redundancies can create de novo vulnerabilities that are specific to cancer cells. In this regard, paralog genes are of particular interest, as the loss of one paralog gene can render tumour cells dependent on a remaining paralog. To systematically identify cancer-relevant paralog dependencies, we searched for candidate dependencies using CRISPR screens and publicly available loss-of-function datasets. Our analysis revealed >2,000 potential candidate dependencies, several of which were subsequently experimentally validated. We provide evidence that DNAJC15-DNAJC19, FAM50A-FAM50B and RPP25-RPP25L are novel cancer relevant paralog dependencies. Importantly, our analysis also revealed unexpected redundancies between sex chromosome genes. We show that chrX- and chrY- encoded paralogs, as exemplified by ZFX-ZFY, DDX3X-DDX3Y and EIF1AX-EIF1AY, are functionally linked so that tumour cell lines from male patients with Y-chromosome loss become exquisitely dependent on the chrX-encoded gene. We therefore propose genetic redundancies between chrX- and chrY- encoded paralogs as a general therapeutic strategy for human tumours that have lost the Y-chromosome.

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