Nosocomial or not? A combined epidemiological and genomic investigation to understand hospital-acquired COVID-19 infection on an elderly care ward.

BACKGROUND: COVID-19 has the potential to cause outbreaks in hospitals. Given the comorbid and elderly cohort of patients hospitalized, hospital-acquired COVID-19 infection is often fatal. Pathogen genome sequencing is becoming increasingly important in infection prevention and control (IPC). AIM: To inform the understanding of in-hospital SARS-CoV-2 transmission in order to improve IPC practices and to inform the future development of virological testing for IPC. METHODS: Patients detected COVID-19 positive by polymerase chain reaction on Ward A in April and May 2020 were included with contact tracing to identify other potential cases. Genome sequencing was undertaken for a subgroup of cases. Epidemiological, genomic, and cluster analyses were performed to describe the epidemiology and to identify factors contributing to the outbreak. FINDINGS: Fourteen cases were identified on Ward A. Contact tracing identified 16 further patient cases; in addition, eight healthcare workers (HCWs) were identified as being COVID-19 positive through a round of asymptomatic testing. Genome sequencing of 16 of these cases identified viral genomes differing by two single nucleotide polymorphisms or fewer, with further cluster analysis identifying two groups of infection (a five-person group and a six-person group). CONCLUSION: Despite the temporal relationship of cases, genome sequencing identified that not all cases shared transmission events. However, 11 samples were found to be closely related and these likely represented in-hospital transmission. This included three HCWs, thereby confirming transmission between patients and HCWs.

Moderate-intensity exercise performed in the evening does not impair sleep in healthy males.

The aim of this study was to examine the effect of single bouts of moderate-intensity aerobic exercise and moderate-intensity resistance exercise performed in the evening on the sleep of healthy young males. The study employed a repeated-measures, counterbalanced, crossover design with three conditions (control, evening aerobic exercise, evening resistance exercise). Twelve male participants (mean ± SD; age: 21.9 ± 2.7 yr) attended the laboratory on three occasions separated by one day between each visit. Between 20:45 h and 21:30 h, participants completed either no exercise, 30 min of aerobic exercise at 75%HRmax, or 30 min of resistance exercise corresponding to 75% of 10-repetition maximum. A 9-h sleep opportunity was provided between 23:00 h and 08:00 h. Core body temperature was measured using ingestible temperature capsules and sleep was measured using polysomnography. Core body temperature was higher during the aerobic exercise and resistance exercise compared to control (p = 0.001). There was no difference in core body temperature at bedtime between the conditions. Sleep onset latency, total sleep time, slow-wave sleep duration, REM sleep duration, wake after sleep onset and sleep efficiency were similar in each condition (p > 0.05). Single bouts of moderate-intensity aerobic exercise or moderate-intensity resistance exercise performed in the evening did not impact subsequent night-time sleep. Core body temperature increased during both forms of exercise, but returned to pre-exercise levels in the 90 min prior to bedtime. Healthy young males can engage in a single bout of moderate-intensity aerobic exercise or moderate-intensity resistance exercise ceasing 90 min before bed without compromising their subsequent sleep.

The impact of a simulated grand tour on sleep, mood, and well-being of competitive cyclists.

AIM: Professional cycling is considered one of the most demanding of all endurance sports. The three major professional cycling stages races (i.e. Tour de France, Giro d'Italia and Vuelta a España) require cyclists to compete daily covering between ~150-200 km for three consecutive weeks. Anecdotal evidence indicates that such an event has a significant effect on the sleep, mood, and general well-being of cyclists, particularly during the latter stages of the event. The primary aim of this study was to simulate a grand tour and determine the impact a grand tour has on the sleep, mood, and general well-being of competitive cyclists. METHODS: Twenty-one male cyclists (M±SD, age 22.2±2.7 years) were examined for 39 days across three phases (i.e. baseline, simulated grand tour, and recovery). Sleep was assessed using sleep diaries and wrist activity monitors. Mood and general well-being were assessed using the Brunel Mood Scale (BRUMS) and Visual Analogue Scales (VAS). RESULTS: The amount and quality of sleep as assessed by the wrist activity monitors declined during the simulated grand tour. In contrast, self-reported sleep quality improved throughout the study. Cyclists' mood and general well-being as indicated by vigour, motivation, physical and mental state declined during the simulated tour. CONCLUSION: Future investigations should examine sleep, mood and well-being during an actual grand tour. Such data could prove instrumental toward understanding the sleep and psychological changes that occur during a grand tour.

Biochemical and pharmacological characterization of AZD1981, an orally available selective DP2 antagonist in clinical development for asthma.

BACKGROUND AND PURPOSE: The discovery of DP2 as a second receptor for PGD2 has prompted the search for antagonists as potential novel therapies based on the associations between PGD2 and disease. Here we describe the biochemical and pharmacological properties of 4-(acetylamino)-3-[(4-chlorophenyl)thio]-2-methyl-1H-indole-1-acetic acid (AZD1981), a novel DP2 receptor antagonist. EXPERIMENTAL APPROACH: Binding to DP2 , functional receptor pharmacology and selectivity were studied in both human and animal systems. KEY RESULTS: AZD1981 displaced radio-labelled PGD2 from human recombinant DP2 with high potency (pIC50 = 8.4). Binding was reversible, non-competitive and highly selective against a panel of more than 340 other enzymes and receptors, including DP1 (>1000-fold selective). AZD1981 inhibited DP2 -mediated shape change and CD11b up-regulation in human eosinophils, shape change in basophils and chemotaxis of human eosinophils and Th2 cells with similar potency. AZD1981 exhibited good cross-species binding activity against mouse, rat, guinea pig, rabbit and dog DP2 . Evaluation in mouse, rat or rabbit cell systems was not possible as they did not respond to DP2 agonists. Agonist responses were seen in guinea pig and dog, and AZD1981 blocked DP2 -mediated eosinophil shape change. Such responses were more robust in the guinea pig, where AZD1981 also blocked DP2 -dependent eosinophil emigration from bone marrow. CONCLUSIONS AND IMPLICATIONS: AZD1981 is a DP2 antagonist that blocks functional responses in eosinophils, Th2 cells and basophils. It exhibited similar potency irrespective of the cell type, DP2 agonist or species used. This selective orally active agent is currently under clinical evaluation as a potential therapeutic agent in respiratory diseases including asthma.

An association and haplotype analysis of porcine maternal infanticide: a model for human puerperal psychosis?

An association analysis using the Illumina porcine SNP60 beadchip was performed to identify SNPs significantly associated with porcine maternal infanticide. We previously hypothesised that this was a good animal model for human puerperal psychosis, an extreme form of postnatal mood disorder. Animals were selected from carefully phenotyped unrelated infanticide and control groups (representing extremes of the phenotypic spectrum), from four different lines. Permutation and sliding window analyses and an analysis to see which haplotypes were in linkage disequilibrium (LD) were compared to identify concordant regions. Across all analyses, intervals on SSCs 1, 3, 4, 10, and 13 were constant, contained genes associated with psychiatric or neurological disorders and were significant in multiple lines. The strongest (near GWS) consistent candidate region across all analyses and all breeds was the one located on SSC3 with one peak at 23.4 Mb, syntenic to a candidate region for bipolar disorder and another at 31.9 Mb, syntenic to a candidate region for human puerperal psychosis (16p13). From the haplotype/LD analysis, two regions reached genome wide significance (GWS): the first on SSC4 (KHDRBS3 to FAM135B), which was significant (-logP 5.57) in one Duroc based breed and is syntenic to a region in humans associated with cognition and neurotism; the second on SSC15, which was significant (-log10P 5.68) in two breeds and contained PAX3, which is expressed in the brain.

The polymorphism analysis of CD169 and CD163 related with the risk of porcine reproductive and respiratory syndrome virus (PRRSV) infection.

Porcine reproductive and respiratory syndrome virus (PRRSV) could infect porcine alveolar macrophages (PAM), and the CD169 and CD163 are identified as critical receptors on the surface of PAM, but whether the single nucleotide polymorphisms (SNPs) of these genes could influence the infection is remain unclear. In this study, we identified totally 6 SNPs for CD169 (G1640T, C1654A, C4175T) and CD163 (G2277A, A2552G and C2700A), and evaluated their associations with PRRSV infection using two classified methods in a 524 pig population to investigate the effects of mutations on the PRRSV receptors. The pigs with genotypes of AA of CD169-C1654A, CT of CD169-C4175T and AA of CD163-A2552G appeared to resistant to the PRRSV infection by the combination of two classified results. The results provided fundamental molecular investigation to promote pig breeding with disease resistance. However, the identification of functional changes induced by SNPs and molecular mechanism were need further research.

Association of multi-pathogenic infections with BAT2, CXCL12, Mx1 and EHMT2 variations in pigs.

Porcine reproductive and respiratory syndrome virus (PRRSV), Haemophilus parasuis and Pseudorabies become a widespread problem causing great economic losses associated with reproductive disturbance, respiratory diseases, neonatal mortality, fibrinous polyserositis, meningitis and arthritis in the pig industry. The important candidate genes are assumed to play crucial roles in host defense against the diseases. The aims of this study were to evaluate the variants in HLA-B associated transcript 2 (BAT2), CXCL12, myxovirus resistance protein 1 (Mx1) and EHMT2 genes and their effects on the risk of infection PRRSV and H. parasuis in a case-control (diseased-healthy pigs) population of Duroc × Landrace × LargeWhite. The results showed that the mutations in BAT2, Mx1 and EHMT2 genes were significantly associated with the antibody and the reisk of infection PRRSV and H. parasuis. Those individuals with AA genotype of BAT2 had significantly higher Pseudorabies virus antibody than that with GG and GA (P < 0.05), and the individuals with TT genotype of EHMT2 generated higher Hog Cholera and Pseudorabies virus antibody than that wtih GG and GA (P < 0.01). These results indicated that the polymorphisms in Mx1, BAT2 and EHMT2 genes changed the diseases susceptibility and could be the potential markers assisting the pig breeding selection and disease resistance.

Effects of FUT1 gene mutation on resistance to infectious disease.

Alpha-(1,2)-fucosyltransferase (FUT1) gene has been identified as a candidate gene for regulating the expression of Escherichia coli F18 receptor gene (ECF18R) which promotes adherence of Enterotoxigenic (ETEC) and Verotoxigenic (VTEC) Escherichia coli (E. coli) via F18 fimbriae. In order to illustrate the polymorphisms of FUT1 and their effects on resistance to natural infection by Porcine Respiratory and Reproductive Symdrome Virus (PRRSV) and Haemophilus parasuis, the distributions of different genotypes and the relative risks of disease incidence in pigs were investigated. A total of 1,041 pigs representing three European breeds (Duroc, Landrace and LargeWhite), five Chinese local breeds (Wild pig, Small MeiShan, QinPing, JinHua, and JianLi) and three commercial populations (LargeWhite × JianLi, Duroc × Landrace × LargeWhite and Duroc × wild pig) were selected to analyze the genotype of the FUT1 gene by PCR-RFLP. Only the GG genotype associated with susceptibility to ECF18 bacteria was detected in Chinese local pig breeds and a population of LargeWhite × JianLi, while the AA genotype which confers resistance to ECF18 was detected in two European breeds (Duroc and LargeWhite), two populations of Duroc × wild pig and Duroc × Landrace × LargeWhite. Regarding relative risk of incidence, Duroc × Landrace × LargeWhite with genotypes GG or AG showed greater relative risk (OR = 2.040, P = 0.025; OR = 1.750, P = 0.081, respectively) than those with genotype AA during natural infection by both PRRSV and Haemophilus parasuis. It can be concluded that the mutation of FUT1 gene might play a role in pig infection by multi-pathogens, and that AA may be a favourable genotype for increasing the resistance to disease.

Effects of the polymorphisms of Mx1, BAT2 and CXCL12 genes on immunological traits in pigs.

It is necessary that genetic markers or biomarkers can be used to predict resistance towards a wide range of infectious diseases. In the present study, we estimated the potential markers and measured their relationship with heritabilities of a wide range of immune traits. Polymorphisms in exon 13 of Mx1, intron 25 of BAT2 and intron 3 of CXCL12 were identified by sequencing, and the genotypes were analyzed by PCR-RFLP in a resource population composed of 352 pure breed Landrace piglets at days 0, 17 and 32 after birth. Associations of single-nucleotide polymorphisms (SNPs) in these genes with a variety of immunological traits and antibody levels for pig reproduction and porcine respiratory syndrome virus (PRRSV), pseudorabies virus (PRV) and classical swine fever virus (CSFV) were performed. The performance of GG genotype of BAT2 on hemoglobin concentration (HBG) and hematocrit (HCT) of piglets at day 0 was significantly higher than that of the AA and AG individuals. For Mx1, compared with CT genotype, the pigs with TT or CC generated more PRRS antibody at day 0. The piglets with CT genotype had highly significant difference of PRV antibody from those with CC and TT genotypes at day 0. And the piglets with CC genotype had higher level red blood cell count (RBC), hemoglobin concentration (HBG) and hematocrit (HCT) than those with CT and TT genotypes at day 17. For the C7462G SNP in the intron 3 of CXCL12, the PRV antibody level of piglets with the CG genotype were higher than that of piglets with CC and GG genotypes at day 17, and the mean corpuscular volume (MCV) of GG piglets were larger than that of CC and CG individuals at day 0. At the locus 7331 bp in the intron 3 of CXCL12, there were significantly differences of mean corpuscular hemoglobin concentrations (MCHC) at day 0 and white blood cell count (WBC) at day 32, which showed the trend GG or AG>AA, AA>AG or GG, respectively. The pigs with AA or GG genotype had more platelet distribution width (PDW), mean platelet volume (MPV) and platelet-large cell ratio (PLR) at day 17 than those with AG. The results of this study indicated that polymorphisms in Mx1, BAT2 and CXCL12 genes were significantly associated with the immunological traits in Landrace piglets and had potential application value for marker-assisted selection of pig breeding with disease resistance.

Analysis of X chromosome genomic DNA sequence copy number variation associated with premature ovarian failure (POF).

BACKGROUND: Premature ovarian failure (POF) is a heterogeneous disease defined as amenorrhoea for >6 months before age 40, with an FSH serum level >40 mIU/ml (menopausal levels). While there is a strong genetic association with POF, familial studies have also indicated that idiopathic POF may also be genetically linked. Conventional cytogenetic analyses have identified regions of the X chromosome that are strongly associated with ovarian function, as well as several POF candidate genes. Cryptic chromosome abnormalities that have been missed might be detected by array comparative genomic hybridization. METHODS: In this study, samples from 42 idiopathic POF patients were subjected to a complete end-to-end X/Y chromosome tiling path array to achieve a detailed copy number variation (CNV) analysis of X chromosome involvement in POF. The arrays also contained a 1 Mb autosomal tiling path as a reference control. Quantitative PCR for selected genes contained within the CNVs was used to confirm the majority of the changes detected. The expression pattern of some of these genes in human tissue RNA was examined by reverse transcription (RT)-PCR. RESULTS: A number of CNVs were identified on both Xp and Xq, with several being shared among the POF cases. Some CNVs fall within known polymorphic CNV regions, and others span previously identified POF candidate regions and genes. CONCLUSIONS: The new data reported in this study reveal further discrete X chromosome intervals not previously associated with the disease and therefore implicate new clusters of candidate genes. Further studies will be required to elucidate their involvement in POF.

Analysis of the non-recombining Y chromosome defines polymorphisms in domestic pig breeds: ancestral bases identified by comparative sequencing.

Sequences from 20 amplicons representing nine different loci and 11369bp from the short arm of the pig Y chromosome were compared using pools of DNA from different European and Chinese breeds. A total of 33 polymorphic sites were identified, including five indels and 28 single nucleotide polymorphisms (SNPs). Three high frequency SNPs within the coding regions of SRY were further analysed across 889 males representing 25 European and 25 Asian breeds or Lines, plus a European Line of Meishan. Two haplotypes seen to be associated with 'European' or 'Chinese' origin in the initial SNP discovery phase were found to be the most common in their respective groups of breeds in a more detailed genotyping study. Two further SRY haplotypes are relatively rare. One was found exclusively within Tamworth, at low frequency in Retinto, and in three Chinese breeds (Huai, Sahwutou and Xiaomeishan). The other uncommon haplotype is found exclusively in Bamajiang, two further Chinese breeds (Hangjiang Black and Longling) and two European rare breeds (Mangalica and Linderödssvin), but appears based on comparison with other suids to represent an ancestral sequence.

Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus.

BACKGROUND: Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult. RESULTS: In this report, we have analyzed native host (piglets) gene expression changes in response to acute pseudorabies virus infection of the brain and lung using a printed human oligonucleotide gene set from Illumina. A total of 210 and 1130 out of 23,000 transcript probes displayed differential expression respectively in the brain and lung in piglets after PRV infection (p-value < 0.01), with most genes displaying up-regulation. Biological process and pathways analysis showed that most of the up-regulated genes are involved in cell differentiation, neurodegenerative disorders, the nervous system and immune responses in the infected brain whereas apoptosis, cell cycle control, and the mTOR signaling pathway genes were prevalent in the infected lung. Additionally, a number of differentially expressed genes were found to map in or close to quantitative trait loci for resistance/susceptibility to pseudorabies virus in piglets. CONCLUSION: This is the first comprehensive analysis of the global transcriptional response of the native host to acute alphaherpesvirus infection. The differentially regulated genes reported here are likely to be of interest for the further study and understanding of host viral gene interactions.

Glucocorticoid sensitivity of lipopolysaccharide-stimulated chronic obstructive pulmonary disease alveolar macrophages.

It has been reported that alveolar macrophages from patients with chronic obstructive pulmonary disease (COPD) display glucocorticoid (Gc) resistance. The Gc sensitivity of inflammatory mediators released by COPD macrophages may vary. The objective of this study was to identify Gc-insensitive inflammatory mediators produced by lipopolysaccharide (LPS)-stimulated alveolar macrophages from COPD patients. LPS-stimulated alveolar macrophages from 15 COPD patients, nine smokers (S) and nine healthy non-smokers (HNS) were stimulated with LPS with or without dexamethasone (100 and 1000 nM). Luminex and enzyme-linked immunosorbent assay were used to measure 23 inflammatory mediators. After LPS stimulation there were lower levels of inflammatory mediators in COPD patients and S compared to HNS. There was no difference between groups for the effects of dexamethasone at either concentration (P > 0.05 for all comparisons). Tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and growth-related oncogene (GRO)-alpha displayed the greatest sensitivity to dexamethasone in COPD patients, while IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) were the least sensitive. COPD macrophages have a reduced response to LPS. Gc sensitivity was similar in COPD macrophages compared to controls. We identify some Gc-insensitive cytokines, including GM-CSF, G-CSF and IL-8, that may be involved in the progression of airway inflammation in COPD patients.

Association analysis between pseudorabies antibody and five single-nucleotide polymorphisms in pigs.

Pseudorabies has become endemic and represents a widespread problem for pig production in the world, causing great economic losses associated with reproductive failure and neonatal mortality in the pig industry. Most diseases are the results of mutations of functional genes. Single-nucleotide polymorphisms (SNPs) from the coding regions of the mediators of pro-inflammatory responses or other candidate genes in pigs could indicate their potential involvement in susceptibility or resistance to PrV (pseudorabies virus) infection. There have been no previous association studies with candidate host genes that may influence PrV phenotypic traits. In order to perform association studies to identify genes contributing to PrV phenotypes, the genotypes of five SNPs from four genes (IL10, CXCL12, BAT2 and EHMT2) were determined for 178 sow samples using a high throughput microarray-based methodology. PrV antibodies were tested by enzyme-linked immunosorbent assay (ELISA) to determine whether there was an association between antibody levels and particular genotypes. The association between SNP genotypes and the PrV antibody levels were analysed using the Duncan method of one-way ANOVA procedure using the SAS (Statistical Analysis Systems) software package. The results showed that the glycoprotein E-ELISA antibody level of pigs with genotypes 11(AA) and 12(AG) was significantly higher than in pigs with genotype 22(GG) (P < 0.05) of SNP in the gene EHMT2-SNP2. The SNP of EHMT2 may be an effective potential tool to identify susceptible and resistant animals when used in conjunction with traditional selection methods.

Putting the Diabetes Prevention Program into practice: a program for weight loss and cardiovascular risk reduction for patients with metabolic syndrome or type 2 diabetes mellitus.

BACKGROUND: The increasing incidence and prevalence of metabolic syndrome and type 2 diabetes mellitus (DM) have significant implications on health world-wide. Large clinical trials have demonstrated the effectiveness of a comprehensive lifestyle program with a goal of moderate weight loss (5-7%) and regular exercise (150 minutes/week), resulting in a significant decrease in the incidence of type 2 DM and cardiovascular risk. METHODS: This study reports on the translation of the multi-center Diabetes Prevention Program (DPP) into a cardiac rehabilitation program, utilizing the expertise and experience of a cardiac rehabilitation program staff. The study adapted materials from the DPP to develop a program that fit local needs for diabetes prevention. RESULTS: Most participants completed the program (11 months) and their moderate weight loss was maintained for 11-12 months. At 11-12 months, waist circumference was reduced by approximately 2 inches, percent body fat was reduced by 5% (11% relative decrease, p<.05), weight was decreased by 10.1 pounds (p<.05), and blood pressure was reduced 8/3 mm Hg (p<.05). Exercise, nutrition, glucose, triglycerides, LDL-cholesterol and HDL cholesterol were all were significantly improved at 11-12 months (p<.05). CONCLUSIONS: Efforts to improve lifestyle and reduce body weight are important to patients at risk of developing diabetes. This program demonstrates that an intensive effort can significantly improve lifestyle and reduce body weight in patients with DM or at risk for DM. A program that simulates cardiac rehabilitation, translated from a successful clinical trial into practice, resulted in significant reduction and improvement in metabolic outcomes and cardiovascular risk. Support for cardiac rehabilitation from insurers to develop similar programs is encouraged and deserves further study.

A novel antagonist of prostaglandin D2 blocks the locomotion of eosinophils and basophils.

BACKGROUND: Chemoattractant receptor homologous molecule of Th2 cells (CRTH2) has been shown to mediate the chemotaxis of eosinophils, basophils and Th2-type T lymphocytes. The major mast cell product prostaglandin (PG) D(2) is considered to be the principal ligand of CRTH2. MATERIALS AND METHODS: We developed a novel CRTH2 antagonist, AZ11665362 [2,5-dimethyl-3-(8-methylquinolin-4-yl)-1H-indole-1-yl]acetic acid, and characterized its efficacy in binding assay in HEK293 cells, eosinophil and basophil shape change assay and migration assay, platelet aggregation and eosinophil release from guinea pig bone marrow. The effects were compared with ramatroban, the sole CRTH2 antagonist clinically available to date. RESULTS: AZ11665362 bound with high affinity to human and guinea pig CRTH2 expressed in HEK293 cells and antagonized eosinophil and basophil shape change responses to PGD(2). AZ11665362 was without effect on the PGD(2)-induced inhibition of platelet aggregation. In contrast, AZ11665362 effectively inhibited the in vitro migration of human eosinophils and basophils towards PGD(2). The release of eosinophils from the isolated perfused hind limb of the guinea pig was potently stimulated by PGD(2), and this effect was prevented by AZ11665362. In all assays tested, AZ11665362 was at least 10 times more potent than ramatroban. CONCLUSIONS: AZ11665362 is a potent CRTH2 antagonist that is capable of blocking the migration of eosinophils and basophils, and the rapid mobilization of eosinophils from bone marrow. AZ11665362 might hence be useful for the treatment of allergic diseases.

Characterization of the porcine KIT ligand gene: expression analysis, genomic structure, polymorphism detection and association with coat colour traits.

Kit ligand (KITLG) is the ligand for the type III receptor tyrosine kinase KIT. Studies of the KIT/KITLG pathway in a number of mammalian species have shown that it is important for the development of stem cell populations in haematopoietic tissues, germ cells in reproductive organs and the embryonic migrating melanoblasts that give rise to melanocytes. Consequently, mutations in the pathway may result in a range of defects including anaemia, sterility and de-pigmentation. The cDNA sequence of the porcine KITLG gene has been reported previously, and is an attractive candidate locus for moderating coat colour in pigs. In this paper we report the gene structure and physical mapping of the porcine gene. We also report the identification of polymorphisms in the gene, one of which was used to confirm linkage to chromosome 5. Preliminary RNA expression studies using a panel of tissues have shown that in addition to the known variant lacking exon 6, there is alternative splicing of exon 4. However, little evidence was found for the KITLG gene being linked to variation in colour in a Meishan x Large White cross.

Analysis of sex chromosome abnormalities using X and Y chromosome DNA tiling path arrays.

BACKGROUND: Array comparative genomic hybridisation is a powerful tool for the detection of copy number changes in the genome. METHODS: A human X and Y chromosome tiling path array was developed for the analysis of sex chromosome aberrations. RESULTS: Normal X and Y chromosome profiles were established by analysis with DNA from normal fertile males and females. Detection of infertile males with known Y deletions confirmed the competence of the array to detect AZFa, AZFb and AZFc deletions and to distinguish between different AZFc lesions. Examples of terminal and interstitial deletions of Xp (previously characterised through cytogenetic and microsatellite analysis) have been assessed using the arrays, thus both confirming and refining the established deletion breakpoints. Breakpoints in iso-Yq, iso-Yp and X-Y translocation chromosomes and X-Y interchanges in XX males are also amenable to analysis. DISCUSSION: The resolution of the tiling path clone set used allows breakpoints to be placed within 100-200 kb, permitting more precise genotype/phenotype correlations. These data indicate that the combined X and Y tiling path arrays provide an effective tool for the investigation and diagnosis of sex chromosome copy number aberrations and rearrangements.