Q-BANDING OF CHROMOSOMES IN HUMAN SPONTANEOUS ABORTIONS

1978 ◽  
Vol 20 (3) ◽  
pp. 415-425 ◽  
Author(s):  
David H. Carr ◽  
Milan M. Gedeon

Chromosome studies of 242 spontaneous abortions were carried out by Q-banding technique. The abortuses were selected for study because they were phenotypically abnormal, had not progressed beyond 12 weeks development, or were from women with repeated abortions. Chromosome anomalies were found in 126 (52%) of the abortuses. Of these, 71 (56%) were trisomies. Trisomies were found for all the autosomes except Nos. 1, 3, 5, 11, 17 and 18. Triploidy was the second commonest anomaly in this series, making up 26 (21%) of the total anomalies. About 70% of these had an XXY sex chromosome complement. Only 16 (13%) of the abortuses had X monosomy, a lower frequency than would be expected in an unselected study. Tetraploidy was found in 8 abortuses and the 5 remaining specimens had various anomalies. These included 3 translocations, a trisomy 21,X monosomy and a ring chromosome 13. Except for the greater frequency of XXY than XXX sex chromosomes in the triploids, there was no evidence of a distortion of the sex ratio, either among the trisomic or among the chromosomally normal abortuses.

Endocrinology ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 1092-1104 ◽  
Author(s):  
Xuqi Chen ◽  
Rebecca McClusky ◽  
Yuichiro Itoh ◽  
Karen Reue ◽  
Arthur P. Arnold

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.


2021 ◽  
Author(s):  
Sarah R Ocanas ◽  
Victor A Ansere ◽  
Kyla B Tooley ◽  
Niran Hadad ◽  
Ana J Chucair-Elliott ◽  
...  

Sex differences in the brain as they relate to health and disease are often overlooked in experimental models. Many neurological disorders, like Alzheimer's disease (AD), multiple sclerosis (MS), and autism, differ in prevalence between males and females. Sex differences originate either from differential gene expression on sex chromosomes or from hormonal differences, either directly or indirectly. To disentangle the relative contributions of genetic sex (XX v. XY) and gonadal sex (ovaries v. testes) to the regulation of hippocampal sex effects, we use the "sex-reversal" Four Core Genotype (FCG) mouse model which uncouples sex chromosome complement from gonadal sex. Transcriptomic and epigenomic analyses of hippocampal RNA and DNA from ~12 month old FCG mice, reveals differential regulatory effects of sex chromosome content and gonadal sex on X- versus autosome-encoded gene expression and DNA modification patterns. Gene expression and DNA methylation patterns on the X chromosome were driven primarily by sex chromosome content, not gonadal sex. The majority of DNA methylation changes involved hypermethylation in the XX genotypes (as compared to XY) in the CpG context, with the largest differences in CpG islands, promoters, and CTCF binding sites. Autosomal gene expression and DNA modifications demonstrated regulation by sex chromosome complement and gonadal sex. These data demonstrate the importance of sex chromosomes themselves, independent of hormonal status, in regulating hippocampal sex effects. Future studies will need to further interrogate specific CNS cell types, identify the mechanisms by which sex chromosome regulate autosomes, and differentiate organizational from activational hormonal effects.


2021 ◽  
Author(s):  
Monica M Sheffer ◽  
Mathilde M Cordellier ◽  
Martin Forman ◽  
Malte Grewoldt ◽  
Katharina Hoffmann ◽  
...  

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.


2021 ◽  
Author(s):  
Elizabeth A. Sneddon ◽  
Lindsay N. Rasizer ◽  
Natalie G. Cavalco ◽  
Asa H. Jaymes ◽  
Noah J. Ostlie ◽  
...  

AbstractAlcohol use and high-risk alcohol drinking behaviors among women are rapidly rising. In rodent models, females typically consume more ethanol (EtOH) than males. Here, we used the Four Core Genotypes (FCG) mouse model to investigate the influence of gonadal hormones and sex chromosome complement to EtOH drinking behaviors. FCG mice were given access to escalating concentrations of EtOH in a two-bottle, 24-h continuous access drinking paradigm to assess consumption and preference. Relapse-like behavior was measured by assessing escalated intake following repeated cycles of deprivation and re-exposure. Twenty-four hour EtOH consumption was greater in mice with ovaries (Sry−), relative to those with testes, and in mice with the XX chromosome complement, relative to those with XY sex chromosomes. EtOH preference was higher in XX vs. XY mice but not influenced by gonad type. Escalated intake following repeated cycles of deprivation and re-exposure emerged only in XX mice (vs. XY). These results demonstrate that aspects of EtOH drinking behavior may be independently regulated by sex hormones and chromosomes and inform our understanding of the neurobiological mechanisms which contribute to EtOH dependence in male and female mice. Future investigation of the contribution of sex chromosomes to EtOH drinking behaviors is warranted.


2011 ◽  
Vol 80 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Dagmara Kwolek ◽  
Andrzej J. Joachimiak

Sex-ratio bias in seeds of dioecious <em>Rumex</em> species with sex chromosomes is an interesting and still unsettled issue. To resolve gender among seeds of <em>R. acetosa</em> and <em>R. thyrsiflorus</em> (two species with an XX/XY1Y2 sex chromosome system), this work applied a PCR-based method involving DNA markers located on Y chromosomes. Both species showed female-biased primary sex ratios, with female bias greater in <em>R. acetosa</em> than in <em>R. thyrsiflorus</em>. The observed predominance of female seeds is consistent with the view that the female biased sex ratios in <em>Rumex </em>are conditioned not only postzygotically but also prezygotically.


2020 ◽  
Author(s):  
India Nichols ◽  
Scott Vincent ◽  
September Hesse ◽  
J. Christopher Ehlen ◽  
Allison Brager ◽  
...  

AbstractPoor sleep is a hazard of daily life that oftentimes cannot be avoided. Gender differences in daily sleep and wake patterns are widely reported; however, it remains unclear how biological sex, which is comprised of genetic and endocrine components, directly influences sleep regulatory processes. In the majority of model systems studied thus far, sex differences in daily sleep amount are predominant during the active (wake) phase of the sleep-wake cycle. The pervasiveness of sex differences in sleep amount throughout phylogeny suggests a strong underlying genetic component. The goal of the current study is to determine if sex differences in active-phase sleep amount are dependent on sex chromosomes in mice.Sleep was examined in the four-core genotype (FCG) mouse model, whose sex chromosome complement (XY, XX) is independent of sex phenotype (male or female). In this line, sex phenotype is determined by the presence or absence of the Sry gene, which is dissociated from the Y chromosome. Polysomnographic sleep recordings were obtained from gonadectomized (GDX) FCG mice to examine spontaneous sleep states and the ability to recover from sleep loss. We report that during the active-phase, the presence of the Sry gene accounts for most sex differences during spontaneous sleep; however, during recovery from sleep loss, sex differences in sleep amount are partially driven by sex chromosome complement. These results suggest that genetic factors on the sex chromosomes encode the homeostatic response to sleep loss.


1982 ◽  
Vol 60 (11) ◽  
pp. 2866-2878 ◽  
Author(s):  
William S. Procunier

Cytological descriptions and phylogenetic relationships are presented for the genus Cnephia s. str. All members are male achiasmate. Cnephia lapponica is unique in that its basic chromosome complement is reduced from n = 3 to n = 2 metacentrics as a result of a fusion of chromosomes II and III. Sex chromosome differentiation varies from nonobservable in C. ornithophilia and C. eremites through C. pecuarum in which the standard and IS-5 sequences are distributed differentially over X and Y chromosomes, to the polytypic system of C. lapponica in which the X chromosome is fixed for expression of the nucleolar organizer (NO) and the Y chromosome for nonexpression. Further, in a Norwegian population of C. lapponica, males are additionally interchange heterozygotes. Thus, a multiple sex chromosome system exists in which all the chromosomes are sex chromosomes. Closest members occur sympatrically and differ by sex chromosomes and at least one fixed inversion; more distant taxa differ by a number of fixed inversions as well as sex chromosomes. The identical bands 17B and 24C, which appear in a thin or enhanced form, are polymorphic, sex-linked, fixed, or lost in different members of the group. This study supports a model for sympatric speciation.


2018 ◽  
Author(s):  
Ajay Nadig ◽  
Paul K. Reardon ◽  
Jakob Seidlitz ◽  
Cassidy L. McDermott ◽  
Jonathan D. Blumenthal ◽  
...  

AbstractSex chromosome aneuploidy (SCA) enhances risk for several psychiatric disorders associated with the limbic system, including mood and autism spectrum disorders. These patients provide a powerful genetics-first model for understanding the biological basis of psychopathology. Additionally, these disorders are frequently sex-biased in prevalence, further suggesting an etiological role for sex chromosomes. To clarify how limbic anatomy varies across sex and sex chromosome complement, we characterized amygdala and hippocampus structure in a uniquely large sample of patients carrying supernumerary sex chromosomes (n = 132) and typically developing controls (n=166). After correction for sex-differences in brain size, karyotypically normal males (XY) and females (XX) did not differ in volume or shape of either structure. In contrast, all SCAs were associated with lowered amygdala volume relative to gonadally-matched controls. This effect was robust to three different methods for total brain volume correction, including an allometric analysis that derived normative scaling rules for these structures in a separate, typically developing population (n = 79). Hippocampal volume was insensitive to SCA after correction for total brain volume. However, surface-based analysis revealed that SCA, regardless of specific karyotype, was consistently associated with a spatially specific pattern of shape change in both amygdala and hippocampus. In particular, SCA was accompanied by contraction around the basomedial nucleus of the amygdala and an area within the hippocampal surface that cuts across hippocampal subfields. These results demonstrate the power of SCA as a model to understand how copy number variation can precipitate changes in brain systems relevant to psychiatric disease.


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