Background Proctitis is an inflammation of the rectum and may be induced by radiation treatment for cancer. The genetic heritability of developing radiotoxicity and prior role of genetic variants as being associated with side-effects of radiotherapy necessitates further investigation for underlying molecular mechanisms. In this study, we investigated gene expression regulated by genetic variants, and copy number variation in prostate cancer survivors with radiotoxicity. Methods We investigated proctitis as a radiotoxic endpoint in prostate cancer patients who received radiotherapy ( n = 222). We analyzed the copy number variation and genetically regulated gene expression profiles of whole-blood and prostate tissue associated with proctitis. The SNP and copy number data were genotyped on Affymetrix® Genome-wide Human SNP Array 6.0. Following QC measures, the genotypes were used to obtain gene expression by leveraging GTEx, a reference dataset for gene expression association based on genotype and RNA-seq information for prostate ( n = 132) and whole-blood tissue ( n = 369). Results In prostate tissue, 62 genes were significantly associated with proctitis, and 98 genes in whole-blood tissue. Six genes - CABLES2, ATP6AP1L, IFIT5, ATRIP, TELO2 , and PARD6G were common to both tissues. The copy number analysis identified seven regions associated with proctitis, one of which ( ALG1L2) was also associated with proctitis based on transcriptomic profiles in the whole-blood tissue. The genes identified via transcriptomics and copy number variation association were further investigated for enriched pathways and gene ontology. Some of the enriched processes were DNA repair, mitochondrial apoptosis regulation, cell-to-cell signaling interaction processes for renal and urological system, and organismal injury. Conclusions We report gene expression changes based on genetic polymorphisms. Integrating gene-network information identified these genes to relate to canonical DNA repair genes and processes. This investigation highlights genes involved in DNA repair processes and mitochondrial malfunction possibly via inflammation. Therefore, it is suggested that larger studies will provide more power to infer the extent of underlying genetic contribution for an individual’s susceptibility to developing radiotoxicity.

Proctitis is an inflammation of the rectum and may be induced by radiation treatment for cancer. We investigated proctitis as a radiotoxic endpoint in prostate cancer patients who received radiotherapy (n=222). We analyzed the copy number variation and SNP-derived transcriptomic profiles of whole-blood and prostate tissue associated with proctitis. The SNP and copy number data were genotyped on Affymetrix® Genome-wide Human SNP Array 6.0. Following QC measures, the genotypes were used to obtain gene expression by leveraging GTEx, a reference dataset for gene expression association based on genotype and RNA-seq information for prostate (n= 132) and whole-blood tissue (n=369). In prostate tissue, 62 genes were significantly associated with proctitis, and 98 genes in whole-blood tissue. Six genes - CABLES2, ATP6AP1L, IFIT5, ATRIP, TELO2 , and PARD6G were common to both tissues. The copy number analysis identified seven regions associated with proctitis, one of which ( ALG1L2) was also associated with proctitis based on transcriptomic profiles in the whole-blood tissue. The genes identified via transcriptomics and copy number variation association were further investigated for enriched pathways and gene ontology. Some of the enriched processes were DNA repair, mitochondrial apoptosis regulation, cell-to-cell signaling interaction processes for renal and urological system, and organismal injury.

Ancestry informative single nucleotide polymorphisms (SNPs) can identify biogeographic ancestry (BGA); however, population substructure and relatively recent admixture can make differentiation difficult in heterogeneous Hispanic populations. Utilizing unrelated individuals from the Genomic Origins and Admixture in Latinos dataset (GOAL, n = 160), we designed an 80 SNP panel (Setser80) that accurately depicts BGA through STRUCTURE and PCA. We compared our Setser80 to the Seldin and Kidd panels via resampling simulations, which models data based on allele frequencies. We incorporated Admixed American 1000 Genomes populations (1000 G, n = 347), into a combined populations dataset to determine robustness. Using multinomial logistic regression (MLR), we compared the 3 panels on the combined dataset and found overall MLR classification accuracies: 93.2% Setser80, 87.9% Seldin panel, 71.4% Kidd panel. Naïve Bayesian classification had similar results on the combined dataset: 91.5% Setser80, 84.7% Seldin panel, 71.1% Kidd panel. Although Peru and Mexico were absent from panel design, we achieved high classification accuracy on the combined populations for Peru (MLR = 100%, naïve Bayes = 98%), and Mexico (MLR = 90%, naïve Bayes = 83.4%) as evidence of the portability of the Setser80. Our results indicate the Setser80 SNP panel can reliably classify BGA for individuals of presumed Hispanic origin.

In a criminal paternity case, which involved analysis of the product of conception, a rare circumstance was observed. The product of conception was triploidy, apparently due to an egg fertilized by two sperm. Since there is little guidance on how to calculate the probability of the DNA evidence given some basic hypotheses, the formulae were derived and are presented herein. These approaches could provide guidance for similar situations if they arise.

We report here a novel multiplexed DNA analysis system consisting of 20 Alu markers and Amelogenin for analysis of highly degraded forensic biological samples. The key to the success of the system in obtaining results from degraded samples is the primer design yielding small amplicon size (60–125 bp) for all 20 markers. The markers included in the InnoTyper® 21 system are bi-allelic, having two possible allelic states (insertion or null) and thus termed INNULs. The markers are short interspersed nuclear elements (SINEs), a category of retrotransposable elements (REs) which are non-coding genomic DNA repeat sequences, or "mobile insertion elements," comprising approximately 40% of the human genome. Alu elements are primate specific SINEs that have reached a copy number in excess of one million in the human genome, which makes these markers highly sensitive and desirable for forensic samples with extremely degraded DNA. Until now however, due to the inherent size difference associated with insertion and no insertion alleles, the use of Alu REs has not been practical for forensic applications. The novel primer design described herein has allowed the development of a multiplexed Alu system yielding fragment sizes amenable to degraded DNA samples, as frequently encountered in missing persons cases or forensic samples such as hair shafts. Although use of Alus in human identity has been studied using single marker amplification and reported before, we report for the first time development and validation of a system with multiplexed RE markers. Studies performed include PCR optimization, species specificity, sensitivity, degradation and inhibition, precision and accuracy, nonprobative samples, mixture, and population database studies. A population study using 592 samples including five populations was performed using InnoTyper 21. The data indicated the random match probability for the combination of these 20 Alu markers was greater than 1 in 3.8 million for the populations studied, indicating the greater statistical power of these autosomal nuclear DNA markers over haplotype systems typically used in such degraded samples. Results demonstrate the system is successful in obtaining results from highly degraded DNA. A sensitivity study performed demonstrated at least 95% recovery of alleles from as low as 50 pg of total input DNA, and partial profiles from as low as 25 pg. This study has demonstrated that the bi-allelic INNULs in the InnoTyper 21 system provide a sensitivity of detection and a power of discrimination that makes them useful for human identification of extremely degraded samples.

Massively parallel sequencing (MPS) offers substantial improvements over current forensic DNA typing methodologies such as increased resolution, scalability, and throughput. The Ion PGM™ is a promising MPS platform for analysis of forensic biological evidence. The system employs a sequencing-by-synthesis chemistry on a semiconductor chip that measures a pH change due to the release of hydrogen ions as nucleotides are incorporated into the growing DNA strands. However, implementation of MPS into forensic laboratories requires a robust chemistry. Ion Torrent’s Hi-Q™ Sequencing Chemistry was evaluated to determine if it could improve on the quality of the generated sequence data in association with selected genetic marker targets. The whole mitochondrial genome and the HID-Ion STR 10-plex panel were sequenced on the Ion PGM™ system with the Ion PGM™ Sequencing 400 Kit and the Ion PGM™ Hi-Q™ Sequencing Kit. Concordance, coverage, strand balance, noise, and deletion ratios were assessed in evaluating the performance of the Ion PGM™ Hi-Q™ Sequencing Kit. The results indicate that reliable, accurate data are generated and that sequencing through homopolymeric regions can be improved with the use of Ion Torrent’s Hi-Q™ Sequencing Chemistry. Overall, the quality of the generated sequencing data supports the potential for use of the Ion PGM™ in forensic genetic laboratories.

Atopic dermatitis (AD), food allergy, allergic rhinitis, and asthma are common atopic disorders of complex etiology. The frequently observed atopic march from early AD to asthma, allergic rhinitis, or both later in life and the extensive comorbidity of atopic disorders suggest common causal mechanisms in addition to distinct ones. Indeed, both disease-specific and shared genomic regions exist for atopic disorders. Their prevalence also varies among races; for example, AD and asthma have a higher prevalence in African Americans when compared with European Americans. Whether this disparity stems from true genetic or race-specific environmental risk factors or both is unknown. Thus far, the majority of the genetic studies on atopic diseases have used populations of European ancestry, limiting their generalizability. Large-cohort initiatives and new analytic methods, such as admixture mapping, are currently being used to address this knowledge gap. Here we discuss the unique and shared genetic risk factors for atopic disorders in the context of ancestry variations and the promise of high-throughput "-omics''-based systems biology approach in providing greater insight to deconstruct their genetic and nongenetic etiologies. Future research will also focus on deep phenotyping and genotyping of diverse racial ancestry, gene-environment, and gene-gene interactions.

Ancestry informative markers (AIMs) can be used to determine population affiliation of the donors of forensic samples. In order to examine ancestry evaluations of the four major populations in the USA, 23 highly informative AIMs were identified from the International HapMap project. However, the efficacy of these 23 AIMs could not be fully evaluated in silico. In this study, these 23 SNPs were multiplexed to test their actual performance in ancestry evaluations. Genotype data were obtained from 189 individuals collected from four American populations. One SNP (rs12149261) on chromosome 16 was removed from this panel because it was duplicated on chromosome 1. The resultant 22-AIMs panel was able to empirically resolve the four major populations as in the in silico study. Eight individuals were assigned to a different group than indicated on their samples. The assignments of the 22 AIMs for these samples were consistent with AIMs results from the ForenSeq(TM) panel. No departures from Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD) were detected for all 22 SNPs in four US populations (after removing the eight problematic samples). The principal component analysis (PCA) results indicated that 181 individuals from these populations were assigned to the expected groups. These 22 SNPs can contribute to the candidate AIMs pool for potential forensic identification purposes in major US populations.

Short Tandem Repeats (STRs) comprise repeats of one to several base pairs. Because of the high mutability due to strand slippage during DNA synthesis, rapid evolutionary change in the number of repeating units directly shapes the range of repeat-number variation according to selection pressure. However, the remaining questions include: Why are STRs causing repeat expansion diseases maintained in the human population; and why are these limited to neurodegenerative diseases? By evaluating the genome-wide selection pressure on STRs using the database we constructed, we identified two different patterns of relationship in repeat-number polymorphisms between DNA and amino-acid sequences, although both patterns are evolutionary consequences of avoiding the formation of harmful long STRs. First, a mixture of degenerate codons is represented in poly-proline (poly-P) repeats. Second, long poly-glutamine (poly-Q) repeats are favored at the protein level; however, at the DNA level, STRs encoding long poly-Qs are frequently divided by synonymous SNPs. Furthermore, significant enrichments of apoptosis and neurodevelopment were biological processes found specifically in genes encoding poly-Qs with repeat polymorphism. This suggests the existence of a specific molecular function for polymorphic and/or long poly-Q stretches. Given that the poly-Qs causing expansion diseases were longer than other poly-Qs, even in healthy subjects, our results indicate that the evolutionary benefits of long and/or polymorphic poly-Q stretches outweigh the risks of long CAG repeats predisposing to pathological hyper-expansions. Molecular pathways in neurodevelopment requiring long and polymorphic poly-Q stretches may provide a clue to understanding why poly-Q expansion diseases are limited to neurodegenerative diseases.

Sir, Sharma and his co-authors are to be congratulated for their excellent and comprehensive suggested first edition of the INdian initiative on Obstructive Sleep Apnoea (INOSA) guidelines published in 20141. Since the guidelines are described as “evidence-based”, without denigrating the quality of their work, the purpose of the present letter is to add a few remarks on two issues briefly touched in these guidelines, which should further enhance justifications of such evidence-based guidelines. These remarks may also be of value to make the guidelines potentially “individualized”, since there is a global shift of paradigms of detection, management and treatment of medical problems of significant public health burden through initiatives such as “precision medicine”2. Since the basic premise of precision medicine is to take into account individual variability in developing strategies of prevention as well as treatment of diseases, the role of genetic predisposition is to be emphasized as a risk factor of obstructive sleep apnoea (OSA) as well as its associated syndromes (OSAS), mentioned in Table II of the guidelines paper1. Our own data3 as well as reviews and notes published on this subject4,5 suggest that candidate gene regions that are shown to be associated with OSA and/or OSAS are not of mere statistical significance detected through epidemiological case-control studies; they have their functional relevance as well. For example, associations of OSA/OSAS with polymorphisms at the peroxisome proliferator-activated receptor-γ (PPARG), and glucagon receptor genes directly explain the co-morbid relationship of OSA/OSAS with centralized obesity, since polymorphisms at these two gene regions are also associated with central adiposity. Likewise, the Leptin (LEP) gene is a critical regulator of adipose tissue mass of body weight, and it operates by inhibiting food intake and stimulating energy expenditure (both of which are involved in mechanistic pathogenesis of obesity6). Consequently, the association of LEP polymorphism with OSA/OSAS is likely to be more than of only statistical significance. The association of APOE polymorphisms with OSA/OSAS could be through the functional involvement of APOE in neurological degeneration and dyslipidaemia4. For such reasons, these genes were listed as candidate genes for OSA/OSAS4. In terms of management and treatment of OSA and its associated co-morbid conditions, identification of such genetic risk factors has at least three important implications. First, such candidate gene discoveries can help in defining phenotypes that may serve as intermediate phenotypes of OSA, which may be used as indicators of more readily treatable precursors or consequences of OSA/OSAS. In this context, it is worthwhile to note that several of the morbid conditions (listed in Table III of the guidelines paper1) as well as the ones we detected7, may be precursor intermediate phenotypes of OSA rather than being consequences of OSA. Irrespective of this, genes underlying such phenotypes would also be the foci of familial hereditary risk factors of OSA/OSAS. This would also help in more precise (and perhaps individualized) diagnosis of OSA, since the algorithm for diagnosis (depicted in Figure 2 of the guidelines paper1) can be revised by incorporating such intermediate phenotypes. Second, genes underlying correlated phenotypes also serve as therapeutic targets for management and treatment for majority of such phenotypes. In the area of cancer treatment, with the use of The Cancer Genome Atlas (TCGA) data, such efforts have been proven to be useful in identifying tissue- or mutation-specific functions of proteins that may be targeted for inhibiting development and progression of otherwise aggressive cancers8. Third, the precise sites of gene associations would allow clinical investigations with respect to ‘individual-specific’ modalities of treatment for OSA/OSAS. For example, individual genotypes at the single nucleotide polymorphism (SNP) sites rs15780, rs405509, rs769455 and rs7412 of the APOE gene, that are associated with OSA3 can be tested to examine if the suggested measures for treating OSA (see Box 5 of the guidelines paper1) work equally well for individuals who are genetically predisposed as compared to others. Similar genotype-specific efficacy studies of different types of positive airway pressure (PAP) can also be performed to examine which type of PAP-therapy works better in individuals who are genetically predisposed for OSA-risk. The second issue that may be further discussed relates to surgical treatment of OSA. We conducted a retrospective analysis of pre- and post-operative (for weight-loss) polysomnographic data from adolescents with severe obesity9. We observed a marked improvement in sleep efficiency and sleep fragmentation with surgical weight loss, which is consistent with the suggestions made in section 5 of the guidelines paper1. However, it may be emphasized that there is now emerging evidence that surgical weight loss results in improvement in quality of life6, through resolution of obesity-associated psychosocial, metabolic, and cardiovascular morbidity. Consequently, it may be suggested that correction of sleep fragmentation could be an important but as yet underappreciated factor influencing changes in other major comorbidities of obesity, including OSA/OSAS. In summation, Sharma et al1 provided a basis of INOSA guidelines that may be further substantiated to attempt diagnosis, management and treatment of OSA and its associated medical adversities, in which evidence-based individualized characteristics of patients may be incorporated for reducing the public health burden of this sleep disorder.

The Texas Center for Health Disparities, a National Institute on Minority Health and Health Disparities Center of Excellence, presents an annual conference to discuss prevention, awareness education, and ongoing research about health disparities both in Texas and among the national population. The 2014 Annual Texas Conference on Health Disparities brought together experts in research, patient care, and community outreach on the "Role of Genomics in Eliminating Health Disparities." Rapid advances in genomics and pharmacogenomics are leading the field of medicine to use genetics and genetic risk to build personalized or individualized medicine strategies. We are at a critical juncture of ensuring such rapid advances benefit diverse populations. Relatively few forums have been organized around the theme of the role of genomics in eliminating health disparities. The conference consisted of three sessions addressing "Gene-Environment Interactions and Health Disparities," "Personalized Medicine and Elimination of Health Disparities," and "Ethics and Public Policy in the Genomic Era." This article summarizes the basic science, clinical correlates, and public health data presented by the speakers.

The Kra-Dai linguistic family includes Thai and Lao as well as a great number of languages spoken by ethnic minorities in Southeast Asia. In Thailand, a dozen of other Kra-Dai languages are spoken in addition to Thai, the national language. The genetic structure of the Kra-Dai-speaking populations in Thailand has been studied extensively using uniparentally inherited markers. To extend this line of genetic investigation, this study used 15 autosomal microsatellites of 500 individuals from 11 populations, belonging to nine Kra-Dai ethnicities, namely, the Kaleung, Phu Thai, Saek, Nyo, Lao Isan, Yuan, Black Tai, Phuan and Lue. These ethnolinguistic groups are dispersed in three different geographic regions of Thailand, that is, Northern, Northeastern and Central. The results show a very low average of pairwised F-st (0.0099), as well as no population substructure based on STRUCTURE analysis, indicating genetic homogeneity within the Kra-Dai-speaking group, possibly owing to shared linguistic ancestry. The Mantel test, an analysis of molecular variance, and the approximate Bayesian computation procedure employed to evaluate potential factors for driving genetic diversity revealed that language is the predominant factor affecting genetic variations, whereas geography is not. The result of distance-based clustering analyses and spatial analysis of molecular variance revealed genetic distinctions of some populations, reflecting the effects of genetic drift and gene flow on allele frequency within populations, in concordance with the result of R-matrix regression. The genetic and linguistic affiliations of the contemporary Kra-Dai-speaking groups are consistent with each other despite certain deviation due to various evolutionary factors that may have occurred during their migrations and resettlements.

Las poblaciones latinoamericanas recibieron desiguales aportes europeos, indígenas y africanos, también diversos según se considere línea paterna, materna, o biparental. En este estudio se analiza la contribución parental masculina en 6 muestras de poblaciones híbridas de Argentina, Colombia, México y Uruguay con 4 microsatélites del cromosoma Y: DYS19, DYS390, DYS391 y DYS393, utilizando los métodos de identidad génica, y coalescencias medias. Las estimaciones mostraron diversas contribuciones europeas, indígenas y africanas, pero que presentaban valores muy dispares entre métodos o de baja significación estadística. Para explicar estas discordancias, se analizó el pasado demográfico de las poblaciones con el test de desbalance; los resultados indican que el crecimiento expansivo de las poblaciones estaría provocando la inexactitud mencionada ya que altera las frecuencias originales de la población. A partir de estos resultados, se aplicó un nuevo método (Vadmix) de análisis de mestizaje basado en la información molecular de los microsatélites y que no tiene las limitaciones de los otros métodos. Se encontró que en todas las regiones analizadas la contribución africana era nula y la indígena claramente mayor a la obtenida por otros métodos, lo cual se relacionaría con la conformación de la población al inicio del proceso de mezcla.

Ancestry informative markers (AIMs) can be used to detect and adjust for population stratification and predict the ancestry of the source of an evidence sample. Autosomal single nucleotide polymorphisms (SNPs) are the best candidates for AIMs. It is essential to identify the most informative AIM SNPs across relevant populations. Several informativeness measures for ancestry estimation have been used for AIMs selection: absolute allele frequency differences ( δ ), F statistics ( F ST ), and informativeness for assignment measure (In). However, their efficacy has not been compared objectively, particularly for determining affiliations of major US populations. In this study, these three measures were directly compared for AIMs selection among four major US populations, i.e., African American, Caucasian, East Asian, and Hispanic American. The results showed that the F ST panel performed slightly better for population resolution based on principal component analysis (PCA) clustering than did the δ panel and both performed better than the In panel. Therefore, the 23 AIMs selected by the F ST measure were used to characterize the four major American populations. Genotype data of nine sample populations were used to evaluate the efficiency of the 23-AIMs panel. The results indicated that individuals could be correctly assigned to the major population categories. Our AIMs panel could contribute to the candidate pool of AIMs for potential forensic identification purposes.

Studies performed in the Andean plateau, one of the highest inhabited areas in the world, have reported that reduced availability of oxygen is associated to fetal growth retardation and lower birth weight, which are established predictors of morbidity and mortality during the first year of life. To test this hypothesis, perinatal variables of neonates born at the Juan Noé Hospital of Arica, Chile, were analyzed in relation to altitude of residence and Aymara ancestry of their mothers. The study population comprised the offspring of 5,295 mothers born between February 2004 and August 2010. Information included birth weight, height, head circumference, gestational age, altitude of residence and socioeconomic status, and was obtained from medical records. Mother´s ancestry was assessed based on surnames which were linked to percentages of Aymara admixture estimates relying on 40 selected ancestry informative markers. After correcting for the effect of multicollinearity among predictor variables, neonates born to mothers with an increased component of Aymara ancestry showed significantly higher birth weight and height at sea level, a marginally significant (p-value 0.06) decrease of birth weight and a significant decrease of height with altitude in comparison with the offspring of mothers with low Aymara ancestry. Since observed tendencies are suggestive of a possible genetic adaptation to hypoxia of the Chilean Aymara, we discuss briefly preliminary evidence related to fetal oxygen transport, particularly polymorphisms in the promoters of the HBG1 and HBG2 genes that are modulators of HbF synthesis, obtained in this ethnic group.

Genetic Distance† Ranajit Chakraborty, Ranajit Chakraborty University of Texas, Houston, TX, USASearch for more papers by this author Ranajit Chakraborty, Ranajit Chakraborty University of Texas, Houston, TX, USASearch for more papers by this author First published: 29 September 2014 https://doi.org/10.1002/9781118445112.stat05384 †This article was originally published online in 2005 in Encyclopedia of Biostatistics, © John Wiley & Sons, Ltd and republished in Wiley StatsRef: Statistics Reference Online, 2014. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Wiley StatsRef: Statistics Reference OnlineBrowse other articles of this reference work:BROWSE BY TOPICBROWSE A-Z RelatedInformation