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At least 19 recordsLinked to original sources
PubMed1975

Thyroid metabolism in the recessive sex-linked dwarf female chicken. 2. Binding of thyroid hormones by serum proteins.

Serum protein profiles were studied together with serum binding sites and capacity for L-thyroxine in dwarf and non-dwarf White Leghorn and White Rock breeds at ages 1 wk., 4 wks. and in laying hens. Serum protein profiles varied with breed, strain and age. The percent gamma-globulin fraction was greater (P less than .05) in dwarf 1 wk. old and laying hens of the White Leghorn breed when compared with the normals. The only difference found in the White Rock breed was a decreased level of albumin in dwarf laying hens. There were no significant differences in the capacity or sites of binding of L-thyroxine to serum proteins although greater amounts of L-thyroxine were bound to globulin fractions in the dwarf. The data were interpreted to suggest that changes in serum protein profiles may have been the result of hypothyroidism at the cellular level but there was no reason to suspect abnormal binding of thyroid hormones to be the cause of that hypothyroidism.

Animals↗
PubMed2025

Extensive Recombination Suppression and Genetic Degeneration of a Young ZW Sex Chromosome System in Halfbeak Fish.

Sex chromosome systems have evolved independently across the tree of life, at different times in the past, and the evolutionary consequences of lacking recombination in sex-linked regions have been characterized in many old-established systems. However, empirical studies of young sex chromosomes are still scarce, especially in vertebrates. Integrating whole-genome sequencing data of two species of halfbeak fish, Hyporhamphus sajori and Hyporhamphus intermedius, we identified the sex-determining system in H. sajori as female heterogamety, involving a large fully sex-linked ZW region (∼26 Mb) on chromosome 5. The closest relative, H. intermedius, has a small sex-linked region on a different chromosome and shows male heterogamety, suggesting at least one turnover in this fish genus. The H. sajori sex-linked region includes two evolutionary strata, but the estimated Z-W divergence times are small, less than 3 million years for the older stratum, which is less than between the two species. Nevertheless, this evolutionarily young W-linked region is enriched with repetitive sequences, differs from the ancestral state by five inversions, and about one-third of its protein-coding genes have already become nonfunctional. Transcriptomic analysis suggests that some form of dosage compensation may already be evolving for some sex-linked genes.

Animals↗
PubMed2026

Two melanic pigment patterns are associated with a sex chromosome-linked oncogene in the mountain swordtail Xiphophorus nezahualcoyotl.

Sex-linked traits are widespread, but their genetic architecture has been challenging to characterize, due in part to the repetitive and structurally complex nature of sex chromosomes. In swordtails and platyfish of the genus Xiphophorus, diverse melanic pigmentation patterns are thought to be controlled by a region on the sex chromosomes classically referred to as the "macromelanophore determining locus". Despite nearly a century of study, the identity of the causal gene remains controversial, partially due to previous inability to fully sequence the sex chromosomes. Here, we characterize and investigate two melanin-based pigmentation phenotypes in the species X. nezahualcoyotl: "spotted side" and "marmoratus". We generate a gapless near-telomere-to-telomere X. nezahualcoyotl assembly and perform GWAS to identify regions associated with pigmentation pattern variation and sex-determination. We find both patterns map near the sex-determining region and to a narrow interval near the oncogene xmrk. By generating additional long-read assemblies of sex chromosomes derived from individuals with distinct phenotypes, we find haplotypes containing xmrk can be both X- and Y-linked, and vary dramatically in gene content, structure, and accumulation of repetitive elements including a newly described composite satellite. This variability may impact the region's stability and affect recombination between haplotypes associated with each pattern. Our results shed light on a longstanding debate surrounding the genetic architecture of sex-linked phenotypes. More generally, we showcase how long-read sequencing can reveal phenotypic variation linked to complex and dynamic genomic regions, which may contribute to the evolution of diverse sex-linked traits.

Journal Article↗
PubMed2026

Tumor Loss of the Y Chromosome Defines a Biological Phenotype Associated with Resistance to Radiotherapy Across Cancer Types.

PURPOSE: Sex-linked determinants of radiotherapy response remain poorly understood. We investigated whether tumor loss of the Y chromosome (LOY) is associated with biological and clinical features of radiotherapy resistance across cancer types. MATERIALS AND METHODS: We integrated publicly available cancer cell-line experimental datasets and clinical data to evaluate the impact of LOY on radiotherapy response. The radiosensitivity of 125 cancer cell lines, stratified by Y chromosome status, was analyzed. Gene expression analyses were performed to identify biological pathways associated with LOY. Clinical associations were examined in 537 male patients treated with radiotherapy across multiple tumor types in The Cancer Genome Atlas. RESULTS: LOY was associated with increased post-radiotherapy survival in cancer cell lines (p < 0.001). Transcriptomic analyses demonstrated LOY-associated alterations in DNA damage response, senescence, longevity, and proliferation pathways. In TCGA tumors, LOY was associated with remodeling of the tumor microenvironment, including altered immune and stromal signatures. Clinically, LOY was associated with inferior survival in common-support overlap-weighted analyses adjusted for age, tumor stage, and TCGA-defined tumor type. CONCLUSION: These findings suggest that tumor LOY is associated with a distinct biological profile characterized by features of radioresistance and adverse clinical outcomes following radiotherapy. Further studies are warranted to determine whether LOY represents a clinically relevant sex-linked determinant of radiotherapy response.

loss of Y chromosome↗
PubMed2025

Influence of Gonadal and Chromosomal Sex on the Brain Transcriptome in a Mouse Species with Natural Sex Reversal.

Sex chromosomes are expected to play a role in shaping the transcriptional architecture of sexual dimorphism, through the direct expression of sex-linked genes, by regulating autosomal genes, or in interactions with hormones. Yet, their degree of involvement remains elusive partly because chromosomal sex (e.g. XX/XY) and gonadal sex (ovaries or testes) are usually inextricably intertwined. They are, however, dissociated in the African pygmy mouse, Mus minutoides, in which a feminizing X (X*) has evolved, resulting in three female genotypes (XX, XX*, and X*Y) and one male genotype (XY). Furthermore, all sex chromosomes are fused to autosomes (neo-sex chromosomes: neo-X, neo-X* and neo-Y). Despite complete sex reversal, X*Y females show distinctive phenotypes with greater fertility, divergent maternal care strategies, and the masculinization of some traits (e.g. enhanced aggressiveness). By comparing the brain transcriptome of the four sexual genotypes, we show that differential gene expression is mainly linked to gonadal sex but also, and significantly, to chromosomal sex. Genes influenced by chromosomal sex are overrepresented on sex-linked genomic regions, and some are strong candidates to explain X*Y-specific behavioral and reproductive traits. Our results also suggest the preferential inactivation of the X* chromosome in XX* females, only in the brain, which could explain their trait similarities with XX females. Overall, we show that sex and neo-sex chromosomes have profoundly impacted the brain transcriptome in ways that reflect their new transmission modes, evolutionary trajectories, and resulting genomic conflicts.

Animals↗
PubMed1978

Selective defect of precursor T cells associated with apparently normal B lymphocytes in severe combined immunodeficiency disease.

Two patients, one with an autosomal and the other a sex-linked form of severe combined immunodeficiency, had more than 95% B cells in their peripheral blood. Despite an increased absolute number of B lymphocytes, the patients were unable to produce serum antibodies. In each patient, geno- or pheno-identical bone marrow transplantation was followed by the visualization of a thymus shadow and the appearance of both cellular and humoral functions. Chromosome of allotype studies showed that the T cell originated from the donor whereas serum immunoglobulins were synthesized by host B cells. In these patients the pathogenesis appears to be a selective defect of bone marrow precursor T cells without concomitant intrinsic B cell defect. The successful outcome of the graft in these two patients, who are now, respectively, 5 years and 11 months of age and free of infections, indicates that the preferred form of therapy in such patients is transplantation of bone marrow stem cells, which populate the thymus and mature slowly into T cells that cooperate fully with host B cells in synthesis of antibody.

B-Lymphocytes↗
PubMed1975

X-linked recessive progressive combined variable immunodeficiency (Duncan's disease).

Of 18 boys in Duncan kindred, 6 died of a lymphoproliferative disease. They exhibited a subtle, progressive combined variable immunodeficiency disease characterised by benign or malignant proliferation of lymphocytes, histiocytosis, and alterations in concentrations of serum-immunoglobulins. Infectious mononucleosis occurred during or preceding terminal events in at least 3 of the cousins. Fever, pharyngitis, lymphadenomegaly, hepatosplenomegaly, atypical lymphocytosis, and a spectrum ranging from agammaglobulinaemia to polyclonal hyper-gammaglobulinaemia occurred. At necropsy, the thymus gland and thymic-dependent areas in the lymph-nodes and spleen were depleted of lymphocytes. Diffuse infiltrates composed of lymphocytes, plasma cells, and histiocytes, some containing erythrocytes, invaded the haematopoietic organs, viscera, and central nervous system. In addition, 2 half-brothers had lymphomas of the ileum and central nervous system. Approximately half the boys, including the half-brothers, were affected, and girls were spared, implying sex-linked recessive inheritance. Various lymphohistiocytoses resemble Duncan's disease, but it is distinctive from them in the mode of inheritance or by histiological characteristics. This study suggests that the Epstein-Barr virus or other viruses triggered the fatal proliferation of lymphocytes and that progressive attrition of T-cell functions allowed uncontrolled lymphoproliferation.

Adult↗
PubMed2026

[Sex-specific depression risk].

Major depression displays significant heritability, and its genetic background has been extensively explored by genome-wide association studies. On the whole, these results indicate a highly polygenic landscape with significant sex-linked differences revealing a higher and more polygenic genetic influence in females than in males.

Humans↗
PubMed1975

[Antibody deficiency states in children].

In more than 2500 immunoelectrophoreses and quantitative immunoglobulin determinations 19 cases of transitory hypogammaglobulinaemia, two cases of sex-linked congenital agammaglobulinaemia, six cases of selective IgA deficiency and nine cases of dysgammaglobulinaemia were diagnosed. In congenital agammaglobulinaemia life-long substitution with gammaglobulin must be instituted. Transitory hypogammaglobulinaemia which occurs mostly at the beginning of the second trimenon usually regresses spontaneously at the age of 15 to 18 months. The increased susceptibility to infections can be overcome by gammaglobulin administration. Dysgammaglobulinaemias with serum concentrations below 400 mg/dl also require gammaglobulin supplements. In IgA deficiency the greatest possible care as regards substitution is indicated because of the danger of severe anaphylactic reactions.

Agammaglobulinemia↗
PubMed2026

A Chromosome-Level Genome Assembly of the Potato Leafhopper Empoasca fabae (Hemiptera: Cicadellidae).

The potato leafhopper, Empoasca fabae (Harris, 1841), is a highly polyphagous, migratory insect pest of eastern North America that feeds on more than 200 herbaceous and woody plant species, causing substantial losses to forage and field crops. Despite its agricultural and ecological importance, no genome has been available for this species. Here, we present the first chromosome-level genome assembly of E. fabae, generated from Oxford Nanopore long reads, Illumina short reads, and Omni-C proximity-ligation data. The final assembly spans 908&#x2005;Mb across 132 scaffolds, with 99.8% of the assembly captured in ten chromosome-length scaffolds (nine autosomes and an X chromosome) with a scaffold N50 of 96.2&#x2005;Mb. The assembly is highly complete, recovering 92.9% of conserved hemipteran single-copy orthologs from protein annotations, and is composed of 47.6% repetitive sequence, dominated by long terminal repeat retrotransposons and unclassified elements. Read-depth comparison between male and female individuals supports assignment of a single sex-linked chromosome, consistent with an XO sex determination system. BRAKER3 gene annotation predicted 31,406 protein-coding genes after retaining the longest isoform per locus. Comparative genome analysis of the two closest related Typhlocybinae species with genomes available, Matsumurasca onukii and Hebata decipiens, revealed extensive chromosome-scale collinearity while defining a shared core gene repertoire. This reference genome provides a foundation for comparative and population genomic studies and for investigating genetic traits in this economically important crop pest species.

Animals↗
PubMed2026

Same Sex Chromosomes With Independent Origins in Haplochromine Cichlids.

Elucidating theories of sex chromosome evolution requires approaches that allow fine scale delimitations of sex-determining regions within a phylogenetic context. This can address whether shared sex chromosomes across related species are due to shared ancestry, or whether genetic sex-determining regions have repeatedly evolved. Haplochromine cichlids, as one of the most successful fish lineages on Earth, have been a focal study system of sex chromosome research, both because of their rapid rate of sex chromosome turnover and the repeated emergence of certain sex chromosomes across the lineage. Here, we newly describe sex chromosomes in members of the earliest branch of the modern haplochromines, the Tropheini, based on whole-genome sequencing data, using a combination of SNP- and kmers-based methods. We show that despite the repeated co-options of ancestral chromosomes LG5 and LG7 in these species, the origins of these sex chromosomes are independent. Investigation of gene functions, allele differences, and sex-biased gene expression within the discovered sex-linked regions provides no evidence that sexual antagonism has driven the repeated evolution of a region on LG5 that overlaps between four of these species. By comparing the sex-determining regions on LG5 and LG7 across haplochromines, we show that a common origin is unlikely, and that while sex chromosomes themselves may be shared between several Haplochromini, the sex-determining genes or mechanism likely differ. This study paves the way to explore newly emerging theories of sex chromosome evolution, such as the role of chromosomal fusion or recombination patterns across the genome.

Animals↗
PubMed2025

Repeated evolution of photoperiodic plasticity by different genetic architectures during recurrent colonizations in a butterfly.

In cases of recurrent colonizations of similar habitats from the same base population, it is commonly expected that repeated phenotypic adaptation is caused by parallel changes in genetic variation. However, it is becoming increasingly clear that similar phenotypic variation may also evolve by alternative genetic pathways. Here, we explore the repeated evolution of photoperiodic plasticity for diapause induction across Swedish populations of the speckled wood butterfly, Pararge aegeria. This species has colonized Scandinavia at least twice, and population genomic results show that one of the candidate regions associated with spatial variation in photoperiodism is situated on the Z-chromosome. Here, we assay hybrid crosses between several populations that differ in photoperiodic plasticity for sex-linked inheritance of the photoperiodic reaction norm. We find that while a cross between more distantly related populations from the two different colonization events shows strong sex-dependent inheritance of photoperiodic plasticity, a cross between two more closely related populations within the oldest colonization range shows no such effect. We conclude that the genotype-phenotype map for photoperiodic plasticity varies across these populations and that similar local phenotypic adaptation has evolved during recurrent colonization events by partly non-parallel genetic changes.

Butterflies↗
PubMed2025

Reproducible autosomal gene expression changes with loss of typical X and Y complement across tumor types.

Although there are known sex differences in cancer incidence, severity, and treatment, the sex chromosomes are typically excluded from genomic analyses because of the unique technical challenges associated with assessing their copy number, sequence variation, and expression. Here we assess sex chromosome complement in three widely-used human genomics datasets from normal (non-cancerous) tissues, primary tumors, and cancer cell lines and study the effects on genome-wide gene expression. Expected sex chromosome complements based on reported patient sex were observed in non-cancerous tissues, but about half of tumors and cancer cell lines showed loss of typical sex chromosome gene expression across tissue types with three categories: loss of chromosome Y (LOY), loss of chromosome X (LOX) and reactivation of the inactive X chromosome (XaXa). Genes consistently differentially expressed in tumors with loss of chromosome X, loss of chromosome Y, or loss of X chromosome inactivation are associated with the hallmarks of cancer and include both sex-linked and autosomal genes from nearly all chromosomes, druggable genes, and genes with molecular functions relevant to cancer signaling, such as kinase activity. Strikingly, tumors that are X0, including tumors from female patients that have lost an X chromosome and tumors from male patients that have lost a Y chromosome, cluster together by gene expression profile. Patients with tumors that have LOX or LOY had poorer survival outcomes compared to those with tumors that had maintained their sex chromosome complement. Further, LOX and LOY eliminates nearly all of the differential gene expression between tumors from different patient sexes, affecting sex chromosomal and autosomal gene expression. Going forward, considering patient sex as well as the entire genome, including assessment of the sex chromosome complement, will provide additional insights into personalized tumor etiology, progression, treatment, and patient outcome.

Journal Article↗
PubMed1975

Motor neurone disease: an immunological study.

The state of the immune system, both humoral and cell-mediated, was evaluated in motor neurone disease (MND) patients. The data obtained for the MND patients were confronted with normal controls and a group of patients affected by nervous diseases not involving the immune system. Some differences were observed between MND patients and normal subjects, namely: increase of WBC and gamma-globulin in MND patients. However, such differences were not observed between MND patients and pathological controls, and therefore are probably due to a higher frequency of infectious complications in MND patients in respect to normal controls. The capacity of the immune system to respond to an adequate stimulus was normal, and no precipitating anti-CNS antibodies were detected in MND sera. Furthermore, no sex-linked differences were observed and the CSF abnormalities observed in 2 out of 16 MND patients were probably reflecting only destruction of CNS cells. The data are discussed in view of the possible pathogenetic mechanisms of MND.

Amyotrophic Lateral Sclerosis↗
PubMed2025

The evolution of separate sexes in waterhemp is associated with surprising chromosomal diversity and complexity.

The evolution of separate sexes is hypothesized to occur through distinct pathways involving few large-effect or many small-effect alleles. However, we lack empirical evidence for how these different genetic architectures shape the transition from quantitative variation in sex expression to distinct male and female phenotypes. To explore these processes, we leveraged the recent transition of Amaranthus tuberculatus to dioecy within a predominantly monoecious genus, along with a sex-phenotyped population genomic dataset, and six newly generated chromosome-level haplotype phased assemblies. We identify a ~3&#x2009;Mb region strongly associated with sex through complementary SNP genotype and sequence-depth-based analyses. Comparative genomics of these proto-sex chromosomes within the species and across the Amaranthus genus demonstrates remarkable variability in their structure and genic content, including numerous polymorphic inversions. No such inversion underlies the extended linkage we observe associated with sex determination. Instead, we identify a complex presence/absence polymorphism reflecting substantial Y-haplotype variation-structured by ancestry, geography, and habitat-but only partially explaining phenotyped sex. Just over 10% of sexed individuals show phenotype-genotype mismatch in the sex-linked region, and along with observation of leakiness in the phenotypic expression of sex, suggest additional modifiers of sex and dynamic gene content within and between the proto-X and Y. Together, this work reveals a complex genetic architecture of sex determination in A. tuberculatus characterized by the maintenance of substantial haplotype diversity, and variation in the expression of sex.

Haplotypes↗
PubMed2025

Chromosomal genome assembly resolves drug resistance loci in the parasitic nematode Teladorsagia circumcincta.

The parasitic nematode Teladorsagia circumcincta is one of the most important pathogens of sheep and goats in temperate climates worldwide and can rapidly evolve resistance to drugs used to control it. To understand the genetics of drug resistance, we have generated a highly contiguous genome assembly for the UK T. circumcincta isolate, MTci2. Assembly using PacBio long-reads and Hi-C long-molecule scaffolding together with manual curation resulted in a 573 Mb assembly (N50 = 84 Mb, total scaffolds = 1,286) with five autosomal and one sex-linked chromosomal-scale scaffolds consistent with its karyotype. The genome resource was further improved via annotation of 22,948 genes, with manual curation of over 3,200 of these, resulting in a robust and near complete resource (96.3% complete protein BUSCOs) to support basic and applied research on this important veterinary pathogen. Genome-wide analyses of drug resistance, combining evidence from three distinct experiments, identified selection around known candidate genes for benzimidazole, levamisole and ivermectin resistance, as well as novel regions associated with ivermectin and moxidectin resistance. These insights into contemporary and historic genetic selection further emphasise the importance of contiguous genome assemblies in interpreting genome-wide genetic variation associated with drug resistance and identifying key loci to prioritise in developing diagnostic markers of anthelmintic resistance to support parasite control.

Animals↗
PubMedDate not supplied

[Voluntary choice of sex. The present state of our knowledge].

Whether we like it or not, the next demand that the modern couple will make after birth control will be voluntary selection of the sex of their babies. Furthermore, this selection does have an undoubted medical value in preventing certain sex-linked congenital or hereditary diseases. Many research workers have turned their attention to these problems over the past years, especially in the U.S.A., in England and in Germany. After a historical review of the progress that has taken place in this area a study has been undertaken into the actual state of research in the U.S.A. and in Germany, in which the country the Federal Government has created a special department for scientific research. Our present knowledge into the methods that are adopted to obtain a foetus of male of female sex up to the present is then briefly explained. The results obtained by the principle research workers have been summarised. These are between 80 and 90 per cent success. The steps that have marked these discoveries in this field that is ill understood by the majority of doctors and the French public are outlined.

Body Temperature↗
PubMed2026

Sex differences in the genetic and causal relationships between depression, smoking, and alcohol use: the role of socioeconomic status.

Major depressive disorder (MDD), smoking, and drinking frequently co-occur, with evidence suggesting these relationships may differ by sex. However, the direction of causality and the extent of sex-specific associations remain unclear. We investigated sex-specific genetic relationships between MDD and substance use phenotypes using genome-wide association studies (GWAS) from the UK Biobank and publicly available sex-stratified GWAS for MDD and problematic alcohol use (PAU). Causal effects were assessed using bidirectional, sex-stratified Mendelian randomization (MR). We further applied multivariable MR (MVMR) to evaluate the influence of socioeconomic status (SES). Genetic correlation analyses indicated significant shared genetic architecture between MDD and all substance use traits in sex-combined GWAS. In sex-specific analyses, the correlation between cigarettes per day and MDD was significantly stronger in females, and drinks per week were correlated with MDD only in females. MR analyses showed that genetic liability to MDD increased the risk of smoking initiation and PAU in females, and was associated with reduced alcohol drinking frequency in males. In contrast, no tested substance use trait showed evidence of a causal effect on MDD in either sex. MVMR adjusting for SES attenuated the association between MDD and smoking initiation. The effect on PAU in females remained. In males, the negative association between MDD and drinking frequency became non-significant after SES adjustment. These findings reveal sex-specific genetic and causal relationships between smoking, drinking, and MDD, and highlight the role of SES as a potential confounder. Incorporating sex and socioeconomic context is critical when examining these associations.

Humans↗