• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.465-470
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• 2002

This study presents results of electro-phoretically detectable isozyme variation in Crossing Block (CB) lines of two-rowed barley maintained by the National Crop Experiment Station. The specific objectives were to determine allelic frequencies at the four Est loci(Est1, Est2, Est4, and Est5) and their distribution over 380CB lines of two-rowed barley. A total of 17 alleles were detected over the four Est loci in these lines. There were 4 alleles (Pr, Al, Ca, and Af at the Est1 locus and their frequencies were 69.7, 1.1, 28.4, and 0.8%, respectively. At the Est2 locus, 5 different alleles (Dr, Fr, Sp, Un and a recessive null allele) were detected and their frequencies were 2.9,84.5,0.5,2.1, and 10%, respectively. four alleles (Nz, Su, At, and null were detected at the Est4 locus and the allelic frequency of Su was about 84%. Four alleles(Mi, Pi, Te, and a null allele(od)) were detected at the Est5 locus and their frequencies were 34.2, 61.0, 2.4, and 2.4%, respectively. Based on the allelic frequencies over the four Est loci, 380 CB lines were classified into 25 genotypes. The most frequent genotypes were G1(Pr-Fr-Su-Mi) and G2(Pr-Fr-Su-Pi), and their frequencies were 28.1 and 39.5%, respectively. The frequencies of other genotypes were less than 10%.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.98-104
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• 2008

We constructed the null mutants of fission yeast Schizosaccharomyces pombe rsml gene that is thought to be involved in mRNA export. Though rsm1 gene is not essential for growth, the null mutant strain constructed by replacing the rsm1-coding region with an $kan^{r}$ gene showed growth retardation and mRNA export defects compared to wild type strain. We constructed double mutants which harbor rsm1 null allele and mutant allele of genes involved in mRNA export. The mex67 or npp106 null allele, when combined with rsm1 null allele, showed an additive effect on growth retardation and mRNA export defects. On the other hand, the thp1 null allele restored the defects of growth and mRNA export of rsm1 null mutant. These results suggest that rsm1 plays a role in mRNA export from the nucleus.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6263-6267
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• 2012

Background: Glutathione-S-transferase (GST) is an important phase II xenobiotic compound metabolizing enzyme family, involved in tolerance to a particular drug or susceptibility to a diseasec. This study focused the GSTM1 and T1 null allele frequency in the Gujarat population with a comparison across other Inter- and Intra-Indian ethnic groups to predict variation in the possible susceptible status. Methods: DNA was isolated by a salting out method and GSTM1 and T1 homozygous null genotypes were detected by multiplex polymerase chain reaction in 504 unrelated individuals. The genotype distribution of null alleles was compared with Indian and non Indian ethnics reported earlier in the literature using Fisher's test. Results: The frequencies of the homozygous null genotypes of GSTM1 and GSTT1 were 20% (95%CI 16.7-23.9) and 35.5% (95%CI 31.4-39.9) respectively. GSTM1 null frequency did not deviate from most other Indian ethnic groups but differed from the majority of those of non Indian ethnicity studied. The frequency of homozygous null type of GSTT1 was significantly higher and deviated from all Indian groups and a few of non Indian ethnicity. Conclusions: Gujarat ethnicity, possibly the most susceptible for GSTT1 dependent drug disposition and diseases regarding effects of pollution. Further, the results have implications for GSTT1 dependent drugs used for treatment, a serious problem which needs to be solved by physicians and clinical researchers.

• Biomedical Science Letters
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• v.17 no.2
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• pp.151-155
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• 2011

Short tandem repeats (STRs) loci are the genetic markers used for forensic human identity test. With multiplex polymerase chain reaction (PCR) assays, STRs are examined and measured PCR product length relative to sequenced allelic ladders. In the repeat region and the flanking region of the commonly-used STR may have DNA sequence variation. A mismatch due to sequence variation in the DNA template may cause allele drop-out (i.e., a "null" or "silent" allele) when it falls within PCR primer binding sites. The STR markers were co-amplified in a single reaction by using commercial PowerPlex$^{(R)}$ 16 system and AmpFlSTR$^{(R)}$ Identifiler$^{(R)}$ PCR amplification kits. Separation of the PCR products and fluorescence detection were performed by ABI PRISM$^{(R)}$ 3100 Genetic Analyzer with capillary electrophoresis. The GeneMapper$^{TM}$ ID software were used for size calling and analysis of STR profiles. Here, this study described a forensic human identity test in which allelic drop-out occurred in the STR system D18S51. During the course of human identity test, two samples with a homozygous (16, 16 and 21, 21) genotype at D18S51 locus were discovered using the PowerPlex$^{(R)}$ 16 system. The loss of alleles was confirmed when the samples were amplified using AmpFlSTR$^{(R)}$ Identifiler$^{(R)}$ PCR amplification kit and resulted in a heterozygous (16, 20 and 20, 21) genotype at this locus each other. This discrepancy results suggest that appropriate measures should be taken for database comparisons and that allele should be further investigated by sequence analysis and be reported to the forensic community.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3925-3929
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• 2013

We aimed to investigate bladder cancer risk with reference to polymorphic variants of cytochrome p450 (CYP) 1A1, CYP1B1, glutathione S-transferase (GST) M1, and GSTT1 genes in a case control study. Polymorphisms were examined in 114 bladder cancer patients and 114 age and sex-matched cancer-free subjects. Genotypes were determined using allele specific PCR for CYP1A1 and CYP1B1 genes, and by multiplex PCR and melting curve analysis for GSTM1 and GSTT1 genes. Our results revealed a statistically significant increased bladder cancer risk for GSTT1 null genotype carriers with an odds ratio of 3.06 (95% confidence interval=1.39-6.74, p=0.006). Differences of CYP1A1, CYP1B1 and GSTM1 genotype frequencies were not statistically significant between patients and controls. However, the specific combination of GSTM1 null, GSTT1 null, and CYP1B1 codon 119 risk allele carriers and specific combination of GSTM1 present, GSTT1 null, and CYP1B1 432 risk allele carriers exhibited increased cancer risk in the combined analysis. We did not observe any association between different genotype groups and prognostic tumor characteristics of bladder cancer. Our results indicate that inherited absence of GSTT1 gene may be associated with bladder cancer susceptibility, and specific combinations of GSTM1, GSTT1 and CYP1B1 gene polymorphisms may modify bladder cancer risk in the Turkish population, without any association being observed for CYP1A1 gene polymorphism and bladder cancer risk.

• Genomics & Informatics
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• v.5 no.2
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• pp.61-67
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• 2007

The allele frequencies of markers as well as linkage disequilibrium (LD) can be changed in cases due to the LD between markers and the disease allele, exhibiting spurious associations of markers. To identify the true association, classical statistical tests for dealing with confounders have been applied to draw a conclusion as to whether the association of variants comes from LD with the known disease allele. However, a more direct test considering LD using estimated haplotype frequencies may be more efficient. The null hypothesis is that the different allele frequencies of a variant between cases and controls come solely from the increased disease allele frequency and the LD relationship with the disease allele. The haplotype frequencies of controls are estimated using the expectation maximization (EM) algorithm from the genotype data. The estimated frequencies are applied to calculate the expected haplotype frequencies in cases corresponding to the increase or decrease of the causative or protective alleles. The suggested method was applied to previously published data, and several APOE variants showed association with Alzheimer's disease independent from the APOE ${\varepsilon}4$ variant, rs429358, regardless of LD showing significant simulated p-values. The test results support the possibility that there may be more than one common disease variant in a locus.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4739-4742
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• 2013

Carboplatin, a second generation platinum drug, is widely used to treat different types of cancers. However, myelosuppression remains a major consideration in its use. Genetic polymorphisms of enzymes involved in drug disposition can influence therapeutic outcome. The homozygous null deletion of phase II metabolic gene GSTT1 that abolishes its xenobiotic- detoxifying ability may be associated with carboplatin toxicity. Further, since carboplatin generates oxidative stress, polymorphisms of oxidative stress genes that regulate the cellular level of free radicals may have important roles in generating drug- related adverse effects. We here investigated the null polymorphism of GSTT1, and the -463G>A promoter polymorphism of oxidative stress gene myeloperoxidase (MPO) for carboplatin toxicity in a population of northern India. Cancer patients who were treated with carboplatin, and developed toxicity was considered. The study group comprised of 10 patients who developed therapy- related adverse effects. Peripheral blood was taken from patients for DNA isolation. GSTT1 null genotype was determined by conducting duplex PCR and MPO-463 G>A was determined by PCR followed by RFLP. Hematologic toxicity was experienced by 5 patients, 2 of them had grade 3 and 4 toxicity and 3 others had grade 2 toxicity. They also had gastrointestinal (GI) toxicity. Remaining 5 individuals developed GI toxicity but no hematological toxicity. While GG homozygous of MPO was present in majority of patients having hematologic toxicity (in 4 out of 5 individuals), one A allele (AG genotype) was present in 4 patients who did not have any hematological toxicity. Thus variant A allele of MPO -463G>A may be related to lower hematological toxicity. These preliminary data, however, are required to be confirmed in larger studies along with other relevant polymorphisms.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.349-356
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• 1987

Insertions of transposable elements in or near a structural gene give rise to null phenotypes, reduced levels of gene expression, or alteration on the tissue-specific pattern of gene expression. Null phenotypes often result from insertions in exons. Reduced levels of gene expression results from insertions in various regions such as promoter region, 5' non-translated region, exon and intron. The maize allele of Adh1-3F1124 is an example of alteration in the tissue-specific patetern of gene expression. Adh1-3F1124 contains a Mu element inserted 31 bp 5' to the transcriptional start site of the wild-type Adh1 activity in seeds and anaerobically-treated seedlings but normal levels in the pollen. Upon the insertion of a transposable element a certain number of host DNA sequences at the insertion site is duplcated. When transposable elements excise, all element sequences are deleted. However, the duplicated host sequences may be left intact or deleted to various extents. This results in null phenotypes, restoration of original levels of gene expression, or altered levels of gene expression. On the basis of effects of transposable-element insertions or excisions on gene expression, the usefulness of transposable ellements for studies on gene expression is discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5037-5042
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• 2012

Background: Tobacco contains agents which generate various potent DNA adducts that can cause gene mutations. Production of DNA adducts may be neutralized by glutathione S transferase (GST) along with other phase I and phase II enzyme systems. The existence of null type of GST among the population increases the susceptibility to various disorders and diseases. The present study focuses on the impact of high tobacco usage and possible null type mutation in GST loci. Methods: Genotypes of GST were detected by multiplex polymerase chain reaction in unrelated 504 volunteers of high tobacco using natives of Gujarat. Allelic frequencies were calculated using Statistical Package for Social Studies-16 software. Hardy Weinberg Equilibrium (HWE) was calculated using Chi square test. Two sided Fisher's significance test was used to compare allelic frequencies of different populations. Results: The frequency of homozygous null genotype of GSTM1 and GSTT1 were 20% (95% CI 16.7-23.9) and 35.5% (95% CI 31.4-39.9) respectively. The GSTM1 and GSTT1 null allele frequency distribution in the Gujarat population was significantly deviating from HWE. GSTT1 null frequency of Gujaratians was significantly higher and different to all reported low tobacco using Indian ethnics, while GSTM1 was not differing significantly. Conclusion: Tobacco usage significantly influences the rate of mutation and frequency of GSTT1 and M1 null types among the habituates. The rate of mutation in GSTT1 loci was an undeviating response to the dose of tobacco usage among the population. This mutational impact of tobacco on GSTT1 postulates the possible gene - environment interaction and selection of null genotype among the subjects to prone them under susceptible status for various cancers and even worst to cure the population with GSTT1 dependent drugs.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1109-1111
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• 2006

The present study was carried out to investigate the blood markers of the Korean native horse. A total number of 158 horses were tested using microhaemagglutination with 11D system reagents (Da, Db, Dc, Dd, De, Df, Dg, Dh, Dk, Dm and Dn). Of the 158 horses, 3 horses showed an unusual D system phenogroups; these phenogroups may be silent (null) alleles, De or Dk and Dc, respectively. Dacdfgm, Dacdfgmn, and Ddegmn phenogroups were recognized. These results present basic information for detecting the genetic markers among the Korean native and alien horses.