PREVALENCE AND MOLECULAR CHARACTERIZATION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE (G6PD) DEFICIENCY IN FEMALES FROM PREVIOUSLY MALARIA ENDEMIC REGIONS IN NORTHEASTERN THAILAND AND IDENTIFICATION OF A NOVEL G6PD VARIANT

Introduction: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common X-linked enzymopathy, highly prevalent in areas where malaria is or has been endemic. Prevalence of G6PD deficiency and characterization of G6PD variants in females from previously malaria endemic areas of northeast Thailand remain unstudied. Methods: Prevalence of G6PD deficiency was determined by a fluorescent spot test (FST) and multiplex allele specific (AS)- and restriction fragment length polymorphic (RFLP)-PCR developed for detection of common G6PD variants in the Thai population. Results: Prevalence of G6PD deficiency in female samples (n = 355) was 18% by FST and 27% by PCR-based genotyping. The most common variant was G6PD Viangchan (54%), followed by G6PD Canton (11%) and G6PD Union (11%); in addition, a novel heterozygous variant, G6PD Khon Kaen (c.305T>C, p.F102S located in the coenzyme-binding domain), was identified. The majority (75%) of G6PD activities of heterozygotes were within the intermediate deficiency range (30-80% of median normal enzyme activity). Conclusion: High prevalence of G6PD deficiency was present in females from northeast Thailand, the majority being due to heterozygosity of G6PD variants. The findings will have a bearing on an inclusion of primaquine in antimalarial-based policies for malaria elimination in populations with high prevalence in G6PD deficiency.

RFLP markers linked to powdery mildew resistance genes Pm1, Pm2, Pm3, and Pm4 in wheat

Near-isogenic lines (NILs) and their recurrent parent Chancellor (Cc) were used to identify restriction fragment length polymorphic markers linked to powdery mildew (Blumeria graminis (DC.) E.O. Speer f.sp. tritici) resistance genes Pm1, Pm2, Pm3, and Pm4 in wheat (Triticum aestivum L. em. Thell). By mapping these polymorphic markers in F2 progenies from crosses of the NILs with Cc, it was found that Pm1 cosegregated with a polymorphic locus detected by DNA probe CDO347; Pm2 was linked to a locus detected by probe BCD1871 with a distance of 3.5 cM; Pm3b was linked to a locus detected by probe BCD1434 with a distance of 1.3 cM; Pm4a cosegregated with Xbcd1231-2A(2) and Xcdo678-2A, and was closely flanked by Xbcd1231-2A(1) and Xbcd292-2A both with a distance of 1.5 cM. Aneuploid mapping of these markers indicated that locus Xcdo347-7A is on 7AL, Xbcd1871-5D on 5DS, Xbcd1434-1A on 1AS, and loci Xbcd292-2A and Xcdo678-2A are on 2AL. The same polymorphic fragments detected in the Pm3b NIL by Xbcd1434-1A were found in Pm3a NIL using several enzyme digestions.Key words: RFLP markers, Pm1, Pm2, Pm3, Pm4, Blumeria graminis (DC.) E.O. Speer f.sp. tritici (Erysiphe graminis f.sp. tritici), wheat (Triticum aestivum L. em. Thell), gene tagging.

A microsatellite linkage map of the porcine genome.

We report the most extensive genetic linkage map for a livestock species produced to date. We have linked 376 microsatellite (MS) loci with seven restriction fragment length polymorphic loci in a backcross reference population. The 383 markers were placed into 24 linkage groups which span 1997 cM. Seven additional MS did not fall into a linkage group. Linkage groups are assigned to 13 autosomes and the X chromosome (haploid n = 19). This map provides the basis for genetic analysis of quantitative inheritance of phenotypic and physiologic traits in swine.

Genetic stability of the D1Z2 region: implications for DNA genotyping and paternity testing

The aim of the present study was to examine a single locus variable number tandem repeat for the purpose of DNA genotyping ("fingerprinting"). DNAs of 175 individuals from five ethnic groups (Black, Chinese, Japanese, Caucasian, and Melanesian) were analyzed. Restriction fragment length polymorphic analysis of random individuals revealed individual specific DNA patterns in all but one group. Among 20 Melanesian inhabitants of the Vanuatu islands in the southwest Pacific, three individuals were found to share a common pattern. This island population represents a "genetic isolate" and illustrates the importance of carrying out population studies on individual ethnic groups of interest. The complexity and the genetic stability of the D1Z2 region as revealed by the probe hMF1 make it an excellent candidate for DNA genotyping in paternity testing as 101 Caucasian individuals each had unique patterns for PstI and SinI digests.Key words: DNA fingerprinting, variable number tandem repeat, paternity testing, DNA genotyping.