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PubMed2004

Strain-specific variants of the mouse Cftr promoter region reveal transcriptional regulatory elements.

Regulation of cystic fibrosis transmembrane conductance regulator (CFTR) mRNA levels is not well understood. Mouse Cftr mRNA shows strain-dependent expression differences that cannot be fully explained by variation at non-Cftr loci. Differences in tracheal and colonic expression appear to be due predominantly to elements linked to Cftr. Fifteen single nucleotide sequence variations were found within 1.4 kb 5' to the translation start site between the inbred lines A/J, C57BL/6J and 129/SvJ. In addition, 129/SvJ carries a 100 bp deletion relative to the other two strains. These variants were investigated by sequentially deleting 5' regions and measuring luciferase reporter activity from transfected, mouse epithelial cell lines derived from pancreatic duct, renal collecting duct, salivary gland and trachea. These assays identified a region between -524 and -834 in the C57BL/6J promoter, but not in A/J or 129/SvJ, capable of repressing expression. Sequence analysis and gel mobility shift assays suggest that the transcription factor MZF is involved in the strain-dependent effect. It was also apparent that several reporter constructs displayed expression differences between cell lines, possibly indicating the presence of tissue-specific elements.

Analysis of Variance↗
PubMed2026

Dual-dimensional profiling of host genomic variations and HPV integration in PD-L1-stratified cervical cancer via Oxford Nanopore Technology.

BACKGROUND: The integration of human papillomavirus (HPV) DNA into the host genome is a key step in the development of HPV-associated cervical cancer (CC). However, the genomic characteristics of host genomic variations and HPV integration within the context of programmed death-ligand 1 (PD-L1) expression stratification have not been systematically investigated. METHODS: Whole-genome sequencing was performed using Oxford Nanopore Technology (ONT) on six samples (three from the high PD-L1 expression group and three from the low PD-L1 expression group). The characteristics of host genomic variations under different PD-L1 expression stratifications were explored, including structural variations (SV), copy number variations (CNV), single nucleotide polymorphisms (SNP), and insertion-deletions (Indel). Subsequently, the distribution features of HPV integration sites were analyzed, different integration types were identified, and pathway analysis was conducted. RESULTS: Whole-genome SV analysis revealed that the total number of SVs and the composition of mutation types were similar between the high and low PD-L1 expression groups, with insertions (INS) and deletions (DEL) predominating in both. These variations were primarily enriched in intergenic regions and introns. In the low PD-L1 expression group, integration events were observed at multiple chromosomal loci, with the most frequent integration occurring in the KLF5 gene region on chromosome 13. No frequently integrated loci were identified in the high PD-L1 expression group. Additionally, four distinct HPV integration breakpoint patterns were preliminarily identified and analyzed. CONCLUSION: PD-L1 expression stratification did not significantly alter the overall genomic instability of the host. However, differences were observed in the distribution patterns of HPV integration sites. These findings provide new insights into the genomic heterogeneity of CC under different PD-L1 expression backgrounds and may lay the groundwork for future research exploring stratified immunotherapy based on HPV integration features.

Humans↗
PubMed2003

A method for the assessment of disease associations with single-nucleotide polymorphism haplotypes and environmental variables in case-control studies.

The rough draft of the human genome map has been used to identify most of the functional genes in the human genome, as well as to identify nucleotide variations, known as "single-nucleotide polymorphisms" (SNPs), in these genes. By use of advanced biotechnologies, researchers are beginning to genotype thousands of SNPs from biological samples. Among the many possible applications, one of them is the study of SNP associations with complex human diseases, such as cancers or coronary heart diseases, by using a case-control study design. Through the gathering of environmental risk factors and other lifestyle factors, such a study can be effectively used to investigate interactions between genes and environmental factors in their associations with disease phenotype. Earlier, we developed a method to statistically construct individuals' haplotypes and to estimate the distribution of haplotypes of multiple SNPs in a defined population, by use of estimating-equation techniques. Extending this idea, we describe here an analytic method for assessing the association between the constructed haplotypes along with environmental factors and the disease phenotype. This method is also robust to the model assumptions and is scalable to a large number of SNPs. Asymptotic properties of estimations in the method are proved theoretically and are tested for finite sample sizes by use of simulations. To demonstrate the use of the method, we applied it to assess the possible association between apolipoprotein CIII (six coding SNPs) and restenosis by using a case-control data set. Our analysis revealed two haplotypes that may reduce the risk of restenosis.

Apolipoprotein C-III↗
PubMed2006

Fine mapping of the keratoconus with cataract locus on chromosome 15q and candidate gene analysis.

PURPOSE: To report the fine mapping of the keratoconus with cataract locus on chromosome 15q and the mutational analysis of positional candidate genes. METHODS: Genotyping of two novel microsatellite markers and a single nucleotide polymorphism (SNP) in the critical region of linkage for keratoconus with cataract on 15q was performed. Positional candidate genes (MORF4L1, KIAA1055, ETFA, AWP1, REC14, KIAA1199, RCN2, FAH, IDH3A, MTHFS, ADAMTS7, MAN2C1, PTPN9, KIAA1024, ARNT2, BCL2A1, ISL2, C15ORF22 (P24B), DNAJA4, FLJ14594, CIB2 (KIP2), C15ORF5, and PSMA4) prioritized on the basis of ocular expression and probable function were screened by PCR-based DNA sequencing methods. RESULTS: We report the refinement of the linkage region for keratoconus with cataract to an interval of approximately 5.5 Mb flanked by the MAN2C1 gene and the D15S211 marker on chromosome 15q. Mutational analysis of positional candidate genes detected many sequence variations and single nucleotide polymorphisms. None of the sequence variants were considered pathogenic as they were also found in unaffected family members and normal control DNA samples. CONCLUSIONS: Fine mapping of the keratoconus with cataract locus on 15q has reduced the linked region to 5.5 Mb, thereby excluding 28 candidate genes. A further 23 candidate genes were excluded by direct sequencing methods, although a pathogenic genomic rearrangement or exonic deletion would not have been detected.

Case-Control Studies↗
PubMed2006

Exploration of methods to identify polymorphisms associated with variation in DNA repair capacity phenotypes.

Elucidating the relationship between polymorphic sequences and risk of common disease is a challenge. For example, although it is clear that variation in DNA repair genes is associated with familial cancer, aging and neurological disease, progress toward identifying polymorphisms associated with elevated risk of sporadic disease has been slow. This is partly due to the complexity of the genetic variation, the existence of large numbers of mostly low frequency variants and the contribution of many genes to variation in susceptibility. There has been limited development of methods to find associations between genotypes having many polymorphisms and pathway function or health outcome. We have explored several statistical methods for identifying polymorphisms associated with variation in DNA repair phenotypes. The model system used was 80 cell lines that had been resequenced to identify variation; 191 single nucleotide substitution polymorphisms (SNPs) are included, of which 172 are in 31 base excision repair pathway genes, 19 in 5 anti-oxidation genes, and DNA repair phenotypes based on single strand breaks measured by the alkaline Comet assay. Univariate analyses were of limited value in identifying SNPs associated with phenotype variation. Of the multivariable model selection methods tested: the easiest that provided reduced error of prediction of phenotype was simple counting of the variant alleles predicted to encode proteins with reduced activity, which led to a genotype including 52 SNPs; the best and most parsimonious model was achieved using a two-step analysis without regard to potential functional relevance: first SNPs were ranked by importance determined by random forests regression (RFR), followed by cross-validation in a second round of RFR modeling that included ever more SNPs in declining order of importance. With this approach six SNPs were found to minimize prediction error. The results should encourage research into utilization of multivariate analytical methods for epidemiological studies of the association of genetic variation in complex genotypes with risk of common diseases.

Cell Line↗
PubMed2001

Significance levels in genome scans.

Genome-wide linkage scans using affected sibpair families are being conducted on many complex diseases, such as type 1 and type 2 diabetes, multiple sclerosis, rheumatoid arthritis, schizophrenia, asthma, cardiovascular diseases, obesity, and alcoholism. Despite extensive efforts by many groups, progress has been exceedingly slow, and only a few genes and some genomic regions involved in complex diseases have been identified. The general picture is one of difficulty in locating disease genes and replication of reported linkages. This results from the fact that complex diseases and traits may result principally from genetic variation that is relatively common in the general population involving a large number of genes, environmental factors, and their interactions. Genome-wide association studies are now feasible through the use of PCR methodologies with pooled DNA samples and microsatellite variation, and more recently single-nucleotide polymorphism (SNP) variation. Issues relating to significance levels in genome-wide linkage and association scans are discussed, and suggestions for dealing with false positive (type I) errors proposed.

Alleles↗
PubMed2002

4th International Meeting on Single Nucleotide Polymorphism and Complex Genome Analysis. Various uses for DNA variations.

At the 4th International Meeting on Single Nucleotide Polymorphism and Complex Genome Analysis (Stockholm, Sweden, 10th-14th October 2001), approximately 100 scientists from more than 20 nations undertook a probing review of latest developments in the field. Despite impressive and still ongoing activities towards SNP discovery and validation, plus efforts towards haplotype exploitation, it was clear that supporting technologies for genotyping are way behind where they need to be. Innate complexity and large variances in aspects of genome function together pose immense challenges that are difficult to surmount in the human situation. In contrast, studies in simpler organisms and population/evolutionary genetics studies are yielding important new insights. Breakthroughs that are being made in understanding the genetic etiology of complex disease tend to involve genes of larger effect or extremely well merited candidates. Linkage studies and proximal phenotypes are being recommended, though the best way forward is still hotly debated. Consequently, many diverse and ambitious projects are underway, from which the data itself will eventually show what is and is not possible.

Genome, Human↗
PubMed2006

Genetic influences in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is a metabolic liver disease with widely variable phenotypes extending from simple steatosis, through nonalcoholic steatohepatitis (NASH) to cirrhosis and hepatocellular carcinoma. Inevitably, this reflects the interplay of well-recognized environmental factors and disease associations such as obesity and insulin resistance with host genetic factors, which are polygenic or complex in nature. Most of the observed phenotypic variability will probably be explained by variations in single nucleotide polymorphism frequency, although knowledge of the effect of most polymorphisms on biologic function is currently limited. Several observational studies of kindred with NASH suggest a genetic contribution. Most data characterizing genetic variation in different NAFLD phenotypes is derived from case-control association studies involving putative candidate genes. These candidate genes have been selected largely based upon the "two-hit hypothesis" of the pathogenesis of NAFLD, although other hypothesis-independent approaches can also be informative in gene selection. Thus far, candidate gene association studies have had significant limitations such as small cohort sizes and poor reproducibility. Rapid technologic developments are increasing the capability of detecting genetic variation. Identification of the genetic contribution to NAFLD will inform theories of disease pathogenesis and progression and ultimately improve management.

Fatty Liver↗
PubMed2003

Genetic variation of human UDP-glucuronosyltransferase: implications in disease and drug glucuronidation.

The uridine diphosphate (UDP)-glucuronosyltransferases (UGTs) are key enzymes in human detoxication of xeno- and endobiotics. Potentially toxic endogenous compounds such as bilirubin, or exogenous compounds such as drugs, pesticides, and carcinogens, are generally transformed into water-soluble glucuronides for excretion in bile and urine. The UGTs are encoded by a multigene family in humans. A relatively small number of human enzymes catalyze the glucuronidation of thousands of compounds. Genetic variations and single nucleotide polymorphisms (SNPs) within the UGT genes are remarkably common, and lead to genetic polymorphisms. The multiplicity of transferases, some exhibiting overlapping substrate specificity, may provide functional compensation for genetic deficit in some cases. Genetic variation may cause different phenotypes by affecting expression levels or activities of individual UGTs. This inter-individual variation in UGTs has resulted in functional deficit affecting endogenous metabolism and leading to jaundice and other diseases. Disruption of the normal metabolic physiology, by the reduction of bile acid excretion or steroid glucuronidation, may lead to cholestasis and organ dysfunction. Deficient glucuronidation of drugs and xenobiotics have an important pharmacological impact, which may lead to drug-induced adverse reactions, and even cancer. Additional novel polymorphisms in this gene family are yet to be revealed and studied, but will have a profound effect on the development of new drugs and therapies.

Animals↗
PubMed2001

Association between an agouti-related protein gene polymorphism and anorexia nervosa.

Anorexia nervosa (AN) is a life threatening disorder affecting mostly adolescent women. It is a dramatic psychiatric syndrome accompanied by severe weight loss, hyperactivity and neuroendocrine changes (reviewed in Refs 1 and 2). Several studies have shown a strong genetic component in AN (reviewed in Ref 3). Recent advances in unraveling the mechanisms of weight control point to a crucial role of the melanocortin-4 receptor (MC4-r) system in regulating body weight. The orexigenic neuropeptide agouti-related protein (AGRP), a MC4-r antagonist, plays a crucial role in maintaining body weight, by inducing food intake. The sequence of the coding region of the human AGRP gene (AGRP) was determined and the AGRP of 100 patients with AN was screened for variations. Three single nucleotide polymorphisms (SNPs) were identified and screened in a further 45 patients and 244 controls. Two alleles were in complete linkage disequilibrium and were significantly enriched in anorectic patients (11%; P = 0.015) compared to controls (4.5%). These data indicate that variations of AGRP are associated with susceptibility for AN. This is possibly caused by defective suppression of the MC4-r by the variant AGRP, leading to a decreased feeding signal, increasing the risk of developing AN. These results implicate that antagonism of the MC4-r might be considered as pharmacotherapy for patients with AN.

Adolescent↗
PubMed2000

The importance of genetic polymorphisms in renal transplantation.

Genetic variations including single nucleotide polymorphisms, dinucleotide repeats and microsatellites have been identified in a number of genes encoding cytokines, cytokine receptors, chemokines and their receptors, adhesion molecules. Several of the polymorphisms are located in the promoter region of the gene, affect transcription or translation, and not infrequently determine the level of expression of the protein product. An interesting and testable hypothesis for the clinical heterogeneity and differential responsiveness in allograft recipients is genetic variation. These nucleotide sequence variations, polymorphisms located in genes contributing to immune repertory and in genes responsible for drug metabolism, are excellent candidates for the differential clinical phenotype.

Cytokines↗
PubMed2026

KCFtools: rapid alignment-free method for introgression screening and GWAS using k-mer profiles.

MOTIVATION: In the era of multiple genome references, researchers often align sequencing reads against distinct assemblies or even multiple references simultaneously. This enables applications such as the detection of introgressed segments or highly variable genomic regions, which are especially prevalent in large-genome crop species such as lettuce or wheat. However, these applications come at the cost of increased computational burden, inconsistencies in mapping methods, and reduced reproducibility across studies. To address these limitations, we developed KCFtools, a Java-based toolkit that identifies the presence and absence of k-mers in nonoverlapping genomic or transcriptomic windows by comparing query and reference genomes. This alignment-free approach enables the efficient computation of an identity score for each window, thereby facilitating robust detection of introgressed or variable regions across genomes. RESULTS: We systematically evaluated the performance and accuracy of the k-mer-based method implemented in KCFtools, benchmarking it against conventional single nucleotide variation-based introgression detection pipelines. Our results demonstrate that KCFtools effectively captures introgressed segments and structurally diverse regions, even in species with fragmented or highly divergent reference genomes. In addition, we extended KCFtools to generate genotype matrices from k-mer variation tables. These matrices are compatible with genome-wide association studies software and allow the identification of loci associated with phenotypic traits. We showcase the utility of this approach by detecting known and novel associations for downy mildew resistance in lettuce, underscoring the pipeline's potential for high-resolution, reference-agnostic population genetic analysis. AVAILABILITY AND IMPLEMENTATION: https://github.com/sivasubramanics/kcftools.

Software↗
PubMed2002

[Implication of single nucleotide polymorphisms in association study: mitochondrial variations as another genetic markers for hypertension].

Although multiple nuclear gene polymorphisms have been identified as potential risk factors for hypertension, the linkage between extranuclear DNA variations and hypertension has been uncertain. We investigated whether mitochondrial DNA(mtDNA) polymorphisms are implicated in Japanese hypertension. We used direct sequencing methods to search for single nucleotide polymorphisms(SNPs) in a hypervariable segment of the mitochondrial control region in each blood sample from 20 hypertensives and 20 normotensives. Then, we determined the distribution of two SNPs, T16223C and C16362T, in 183 hypertensives and 193 healthy subjects in the Aomori population in the northern area of Honshu island of Japan. The relationship between the gene polymorphism and hypertension was evaluated using chi-square test. Seventy SNPs were found there and the number of SNPs in each individual was significantly greater(p = 0.0111) in hypertensives than in normotensives. The C16223 genotype was more frequent in hypertensives than in normotensives(p = 0.0018). There was no significant difference in C16362T variant frequency between the groups. From these results, we conclude that mtDNA SNPs were enriched in Japanese hypertension and that the mtDNA C16223 genotype may be one of the genetic susceptibility factors for hypertension.

DNA, Mitochondrial↗
PubMed2006

Unexpected diversity displayed in cDNAs expressed by the immune cells of the purple sea urchin, Strongylocentrotus purpuratus.

We recently identified a unique family of transcripts, the 185/333 family, that comprise approximately 60% of the mRNAs induced by coelomocytes from the purple sea urchin in response to immunological challenge from lipopolysaccharide. An analysis of 81 full-length cDNAs revealed 67 unique nucleotide sequences encoding 64 different proteins. Diversity of the transcripts was based on 25 sequence blocks, or "elements," which resulted in 22 different element patterns based on their presence or absence. Furthermore, there was a high level of nucleotide variation within elements, including single nucleotide polymorphisms and insertions/deletions, both of which resulted in amino acid sequence variability. The deduced 185/333 proteins contained an NH2-terminal leader, a glycine-rich region with an RGD motif, a histidine-rich region, and a COOH-terminal region. Two 185/333 genes, identified in the partially assembled Strongylocentrotus purpuratus genome, have two exons. The first encoded the leader, and the second encoded the remainder of the predicted protein. Estimates from quantitative PCR indicated that there were approximately 100 alleles in the diploid genome. These results suggested that the purple sea urchin may have mechanisms for generating high levels of diversity in response to immunological challenge that have not been considered previously.

Amino Acid Motifs↗
PubMed2000

The Human Genome Project--an overview.

The human genome sequence will underpin human biology and medicine in the next century, providing a single, essential reference to all genetic information. The international program to determine the complete DNA sequence (3,000 million bases) is well underway. As of January 2000, 50% of the sequence is available in the public domain. A comprehensive working draft is expected this year, and the entire sequence is projected to be finished in 2003. DNA sequencing is carried out on mapped, overlapping bacterial clones of 150-200 kb. The working draft comprises assembled unfinished sequence and is released immediately in the public domain. The draft sequence of each clone is then completed, by closing any remaining gaps and resolving any ambiguities, before the entire sequence is checked, annotated, and submitted to the public databases. The sequence of each clone is finished to an accuracy of >99.99%. The availability of a reference sequence of the genome provides the basis for studying the nature of sequence variation, particularly single nucleotide polymorphisms (SNPs), in human populations. SNP typing is a powerful tool for genetic analysis, and will enable us to uncover the association of loci at specific sites in the genome with many disease traits. SNPs occur at a frequency of approximately 1 SNP/kb throughout the genome when the sequence of any two individuals is compared. Programs to detect and map SNPs in the human genome are underway with the aim of establishing a SNP map of the genome during the next two years. The human genome sequence will provide a complete description of all the genes. Annotation of the sequence with the gene structures is achieved by a combination of computational analysis (predictive and homology-based) and experimental confirmation by cDNA sequencing. Detecting homologies between newly defined gene products and proteins of known function helps to postulate biochemical functions for them, which can then be tested. Establishing the association of specific genes with disease phenotypes by mutation screening, particularly for monogenic disorders, provides further assistance in defining the functions of some gene products, as well as helping to establish the cause of the disease. As our knowledge of gene sequences and sequence variation in populations increases, we will pinpoint more and more of the genes and proteins that are important in common, complex diseases. A more detailed understanding of the function of the human genome will be achieved as we identify sequences that control gene expression. Given the availability of gene sequences, the expression status of genes in particular tissues can be monitored in parallel. By comparing corresponding genomic sequences in different species (for example: man, mouse, chicken, and zebrafish), regions that have been highly conserved during evolution can be identified, many of which reflect conserved functions such as gene regulation. These approaches promise to greatly accelerate our interpretation of the human genome sequence.

Human Genome Project↗
PubMed2001

Evidence for the contribution of point mutations to vlsE variation and for apparent constraints on the net accumulation of sequence changes in vlsE during infection with Lyme disease spirochetes.

In the Lyme disease spirochetes, both the ospE and vlsE gene families have been demonstrated to undergo sequence variation during infection. To further investigate the mechanisms associated with the generation of vls variation, single-nucleotide polymorphism and subsequent DNA sequence analyses were performed on the vlsE gene and its paralog, BBJ51, a related gene with a frameshift mutation. These analyses focused on a series of postinfection clonal populations obtained from mice infected with Borrelia burgdorferi B31MIpc or its clonal derivative, B31MIc53. vlsE, but not BBJ51, was found to undergo sequence changes during infection. Consistent with that reported previously (J.-R. Zhang et al., Cell 89:275-285, 1997) many of the sequence changes appear to have arisen through gene conversion events and to be localized to the variable regions of vlsE. However, analysis of the vlsE nucleotide sequences revealed that some sequence changes were the result of point mutations, as these changes did not have potential contributing sources in the vls cassettes. To determine if sequence changes accumulate in vlsE over long-term infection, the vlsE genes of clonal populations recovered after 7 months of infection in mice were analyzed. While new sequence changes developed, a significant number of these changes resulted in the restoration of the vlsE sequence of the original infecting clone. In addition, we noted that some positions within the variable regions (VR) are stable even though the cassettes possess residues that could contribute to sequence variation through gene conversion. These analyses suggest that the total number of amino acid sequence changes that can be maintained by VlsE levels off during infection. In summary, in this report we demonstrate that the development of point mutations serves as a second mechanism by which vlsE sequence variation can be generated and that the capacity for vlsE variation, while still significant, is less than previously postulated.

Amino Acid Sequence↗
PubMed2002

Larger genetic differences within africans than between Africans and Eurasians.

The worldwide pattern of single nucleotide polymorphism (SNP) variation is of great interest to human geneticists, population geneticists, and evolutionists, but remains incompletely understood. We studied the pattern in noncoding regions, because they are less affected by natural selection than are coding regions. Thus, it can reflect better the history of human evolution and can serve as a baseline for understanding the maintenance of SNPs in human populations. We sequenced 50 noncoding DNA segments each approximately 500 bp long in 10 Africans, 10 Europeans, and 10 Asians. An analysis of the data suggests that the sampling scheme is adequate for our purpose. The average nucleotide diversity (pi) for the 50 segments is only 0.061% +/- 0.010% among Asians and 0.064% +/- 0.011% among Europeans but almost twice as high (0.115% +/- 0.016%) among Africans. The African diversity estimate is even higher than that between Africans and Eurasians (0.096% +/- 0.012%). From available data for noncoding autosomal regions (total length = 47,038 bp) and X-linked regions (47,421 bp), we estimated the pi-values for autosomal regions to be 0.105, 0.070, 0.069, and 0.097% for Africans, Asians, Europeans, and between Africans and Eurasians, and the corresponding values for X-linked regions to be 0.088, 0.042, 0.053, and 0.082%. Thus, Africans differ from one another slightly more than from Eurasians, and the genetic diversity in Eurasians is largely a subset of that in Africans, supporting the out of Africa model of human evolution. Clearly, one must specify the geographic origins of the individuals sampled when studying pi or SNP density.

Africa↗
PubMed2003

Systematic analysis of the ABO gene diversity within exons 6 and 7 by PCR screening reveals new ABO alleles.

BACKGROUND: Mutations critical for ABO blood group phenotypes have predominantly been found in exons 6 and 7 of the ABO gene, both of which encode the catalytic domain of ABO glycosyltransferase. To design rapid and reliable ABO genotyping assays, a profound knowledge of the prevalent alleles is required and a reliable sequence database needs to be established. STUDY DESIGN AND METHODS: A PCR screening system was established consisting of 102 different PCRs, each specific for a single nucleotide (nt) variation. The primer mixes were developed to walk from the 5' to the 3' end of exons 6 and 7 of the ABO gene to screen for nt mutations at 50 known polymorphic sites. A total of 109 unrelated individuals with common and rare ABO characteristics were screened. All blood samples in which the PCR results were inconclusive or inconsistent with the ABO phenotypes were subjected to sequence analysis of exons 6 and 7. RESULTS: The results of PCR screening were conclusive and consistent with the ABO phenotypes in 90 cases. In the remaining 19 cases, PCR screening revealed unusual allele combinations or amplification results that were incompatible with known ABO allele combinations or subgroups predicted by serologic analysis. In these 19 cases, sequencing revealed new ABO alleles (one ABO*Ael allele, one ABO*B(A) allele and two ABO*O alleles) in two individuals with common and seven individuals with variant ABO phenotypes. CONCLUSION: This PCR screening strategy is an effective tool for obtaining deeper insight into the ABO gene diversity and diversification and may be useful to increase the quality of the ABO sequence database.

ABO Blood-Group System↗