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Biomedical subjects

M A Tahir

Publications and source records attributed to M A Tahir.

At least 19 recordsLinked to original sources
PubMed2000

Allelic distribution of nine short tandem repeat (STR), HLA-DQA1, and polymarker loci in an Omani sample population.

Allele frequency distributions of nine short tandem repeat (STR) loci, D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D7S820, and D13S317, HLA-DQA1 and polymarker (PM) loci were studied in a sample population from Sultanate of Oman, Middle East. Blood samples were collected from 162 unrelated individuals. For all STR, HLA-DQA1 and PM loci, no deviations from Hardy-Weinberg equilibrium, based on the exact test, were observed. The most discriminating loci were D18S51 (PD=0.966) and FGA (PD=0.964), while the least informative locus is GYPA (PD=0.585). The allele frequency data may be useful in forensic case work.

Alleles↗
PubMed2000

DNA typing of samples for polymarker, DQA1, and nine STR loci from a human body exhumed after 27 years.

A body was exhumed from the ground after 27 years. Samples of femur bone, tooth, and a fingernail were collected and successfully subjected to DNA extraction, quantitation, amplification, and subsequently typed for DQA1, polymarker, and nine STR loci. All three types of samples were typed for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S17, D7S820, and amelogenin using ABI Prism 377 DNA sequencer.

Autopsy↗
PubMed2000

Distribution of HLA-DQA1, polymarker, CSF1PO, vWA, TH01, TPOX, D16S539, D7S820, D13S317, and D5S818 alleles in East Bengali and West Punjabi populations from Indo-Pak Subcontinent.

Blood samples were collected from 115 individuals residing in the Pakistani state of West Punjab and 81 Bengali individuals residing in the state of East Bengal, India. These samples were analyzed for the loci HLA-DQA1, PM (LDLR, GYPA, HBGG, D7S8, and GC) and eight short tandem repeats: CSF1PO, TPOX, THO1, vWA, D16S539, D7S820, D13S317, and D5S818. Departures from Hardy-Weinberg (HWE) were observed in Punjabi population at LDLR, THO1, D13S317, D5S818, and D16S539 and at CSF1PO and THO1 in Bengali population.

Alleles↗
PubMed1999

Typing of eight short tandem repeat (STR) loci in a Saudi Arabian population.

Allele frequency data for eight short tandem repeat (STR) loci, HUMF13A01, HUMFESFPS, HUMF13B, HUMLPL, HUMCSF1PO, HUMTPOX, HUMTHO1 and HUMvWA, were obtained for unrelated individuals in a Saudi Arabian population. All loci, except F13B (P = 0.037) and LPL (P = 0.035), meet Hardy-Weinberg expectations, based on the exact test. The most informative locus is HUMvWA (PD = 0.936) and the least discriminating is the HUMTPOX locus (PD = 0.820). There was only one observation of a departure from expectation from pairwise locus comparisons. These data can be used for estimating the frequency of STR profiles in a Saudi Arabian population.

Alleles↗
PubMed1999

Distribution of D1S80 alleles in the Bahrainian population.

This study demonstrates that the locus D1S80 is highly polymorphic in the Bahrainian population. There were 24 different D1S80 alleles and 51 distinct genotypes observed in 198 Bahrainians. There was one allele observed that was smaller than the 14 repeat allele. This data set meets the Hardy-Weinberg expectations (HWE) and could be a useful marker for parentage testing and forensic applications.

Alleles↗
PubMed1997

Distribution of HLA-DQA1 alleles in Arab and Pakistani individuals from Dubai, United Arab Emirates.

PCR-based typing of the HLA-DQA1 locus, using allele specific oligonucleotide (ASO) probes and reverse dot blot methodology was used to determine allelic distributions and construct a database for Arab and Pakistani individuals living in Dubai. Genotype and allelic frequencies were calculated, and the data were tested for departures from Hardy-Weinberg (HWE) equilibrium. The most frequent HLA-DQA1 alleles among Dubaian Arabs are DQA1 4 and 1.2. Among Pakistanis, the most frequent allele is also DQA1 4. No significant deviations from HWE were detected.

Alleles↗
PubMed1997

Alu insertion polymorphisms and human evolution: evidence for a larger population size in Africa.

Alu insertion polymorphisms (polymorphisms consisting of the presence/absence of an Alu element at a particular chromosomal location) offer several advantages over other nuclear DNA polymorphisms for human evolution studies. First, they are typed by rapid, simple, PCR-based assays; second, they are stable polymorphisms-newly inserted Alu elements rarely undergo deletion; third, the presence of an Alu element represents identity by descent-the probability that different Alu elements would independently insert into the exact same chromosomal location is negligible; and fourth, the ancestral state is known with certainty to be the absence of an Alu element. We report here a study of 8 loci in 1500 individuals from 34 worldwide populations. African populations exhibit the most between-population differentiation, and the population tree is rooted in Africa; moreover, the estimated effective time of separation of African versus non-African populations is 137,000 +/- 15,000 years ago, in accordance with other genetic data. However, a principal coordinates analysis indicates that populations from Sahul (Australia and New Guinea) are nearly as close to the hypothetical ancestor as are African populations, suggesting that there was an early expansion of tropical populations of our species. An analysis of heterozygosity versus genetic distance suggests that African populations have had a larger effective population size than non-African populations. Overall, these results support the African origin of modern humans in that an earlier expansion of the ancestors of African populations is indicated.

Africa↗
PubMed1997

Distribution of HLA-DQ alpha and polymarker (LDLR, GC, GYPA, HBGG, and D7S8) alleles in Arab and Pakistani populations living in Abu Dhabi, United Arab Emirates.

Randomly collected blood samples from 100 Arabs and 100 Pakistanis residing in Abu Dhabi were analyzed using the HLA-DQ alpha and polymarker (LDLR, GC, GYPA, HBGG, D7S8) PCR based reverse dot blot systems. Allelic frequencies for each allele and observed heterozygosity for each locus were calculated. Departures from Hardy-Weinberg expectations (HWE) were determined using the unbiased estimate of the expected homozygote/ heterozygote frequencies, the likelihood ratio test and the exact test. No significant departures from HWE expectations were detected.

Blood Proteins↗
PubMed1995

Typing of DNA HLA-DQ alpha alleles extracted from human nail material using polymerase chain reaction.

The deoxyribonucleic acid (DNA) typing of human Leukocyte Antigen (HLA) DQ alpha from human fingernails is described. HLA-DQ alpha genotypes can be accurately determined from clipped fingernails. We have typed 26 nails accurately, while one did not give any type since that one sample did not amplify due to the low quantity of DNA. The cut off limit for the digested material to be amplified is approximately 9 mgs of nail material.

Alleles↗
PubMed1995

Restriction fragment length polymorphism (RFLP) typing of DNA extracted from nasal secretions.

The restriction fragment length polymorphism (RFLP) analysis of blood, semen, and other body fluids, has become increasingly important in violent criminal cases. The identification of additional tissues suitable for comparison with suspected donors has obvious potential benefit. One type of tissue, that found in nasal secretions, has previously received little attention with regards to genetic analysis. We collected blood and nasal secretion samples from eight individuals, subjected them to traditional RFLP typing methods, and analyzed the results using probes for loci D2S44, D1S7, D10S28, D4S139, and D17S79. All nasal samples provided high DNA yields and hybridization results that matched the corresponding blood standards. Thus, nasal secretions are shown to have potentially significant evidentiary value.

Blood↗
PubMed1984

Gm(11) grouping of dried bloodstains.

An absorption inhibition method for the detection of gamma marker Gm(11) in dried bloodstains is described. Particular reference is made to the association of Gm(11) with Gm(-1, -2). When a dried bloodstain fails to inhibit anti-Gm(1) and anti-Gm(2), this may represent a true Gm(-1, -2) result or there may be insufficient material to inhibit either antibody. The detection of Gm(11) in a bloodstain extract provides an objective means of confirming the apparent absence of Gm(1) and Gm(2) as representing a true Gm(-1, -2) result. This antigen compares very well with other blood group systems with regard to the amount of bloodstain required for analysis and its stability. No evidence is available for preferential loss of Gm(1) and Gm(2) relative to Gm(11) in dried bloodstains.

Blood Group Antigens↗
PubMed1984

Erythrocyte acid phosphatase in human hair root sheaths.

Erythrocyte acid phosphatase (EAP) was observed in human hair root sheaths where hair sheaths and blood samples were collected from 150 donors. In each case, the hairs were typed first for EAP and then confirmed by typing the blood from the same donors. Of the 150 donors checked, EAP activity was found in 135 of the samples; the other 15 samples showed no activity because they contained no sheath cells. Of the 135 samples showing activity, 108 of those were typed accurately in EAP. The remaining 27 samples had EAP activity but with inconclusive findings. In this study, all six common phenotypes were encountered.

Acid Phosphatase↗