Riboflavin in the blood serum,the skin and the venom of some snakes of Burma

Zusammenfassung Es wurden sowohl giftige als auch ungiftige Schlangen aus Burma auf den Gehalt an Flavinen in Blut und Haut untersucht.     

Hypervariable 'minisatellite' regions in human DNA

The human genome contains many dispersed tandem-repetitive 'minisatellite' regions detected via a shared 10-15-base pair 'core' sequence similar to the generalized recombination signal (chi) of Escherichia coli. Many minisatellites are highly polymorphic due to allelic variation in repeat copy number in the minisatellite. A probe based on a tandem-repeat of the core sequence can detect many highly variable loci simultaneously and can provide an individual-specific DNA 'fingerprint' of general use in human genetic analysis.     

Individual-specific 'fingerprints' of human DNA

Simple tandem-repetitive regions of DNA (or 'minisatellites') which are dispersed in the human genome frequently show substantial length polymorphism arising from unequal exchanges which alter the number of short tandem repeats in a minisatellite. We have shown previously that the repeat elements in a subset of human minisatellites share a common 10-15-base-pair (bp) 'core' sequence which might act as a recombination signal in the generation of these hypervariable regions. A hybridization probe consisting of the core repeated in tandem can detect many highly polymorphic minisatellites simultaneously to provide a set of genetic markers of general use in human linkage analysis. We now show that other variant (core)n probes can detect additional sets of hypervariable minisatellites to produce somatically stable DNA 'fingerprints' which are completely specific to an individual (or to his or her identical twin) and can be applied directly to problems of human identification, including parenthood testing.     

A QTL influencing F cell production maps to a gene encoding a zinc-finger protein on chromosome 2p15

F cells measure the presence of fetal hemoglobin, a heritable quantitative trait in adults that accounts for substantial phenotypic diversity of sickle cell disease and beta thalassemia. We applied a genome-wide association mapping strategy to individuals with contrasting extreme trait values and mapped a new F cell quantitative trait locus to BCL11A, which encodes a zinc-finger protein, on chromosome 2p15. The 2p15 BCL11A quantitative trait locus accounts for 15.1% of the trait variance.     

Ha-ras hypervariable alleles in myelodysplasia

The somatic mutation of one of the ras oncogenes is now considered to be a critical step in the pathogenesis of many tumours. Circumstantial evidence also suggests that some individuals may be genetically predisposed to malignancy and a general method used to analyse such disease susceptibility is the study of restriction fragment length polymorphisms (RFLPs) at particular loci. The Harvey ras (Ha-ras) locus includes a hypervariable region (HVR) which consists of a series of 28-base-pair (bp) tandem repeats 3' to the gene. This arrangement gives rise to alleles of a wide range of sizes, making such genetic analysis possible. A previous study reported that white blood cell DNA from cancer patients frequently showed allelic restriction fragments at the Ha-ras locus which were found only rarely in normal unaffected individuals, and it was concluded that the inheritance of such unusual alleles may be linked to a susceptibility to cancer. As this conclusion has major implications we sought to investigate whether this association could be confirmed in patients with myelodysplasia, a common haematological malignancy reported to have the highest frequency of rare alleles. The Ha-ras alleles were characterized in normal healthy individuals and compared with those found in patients with myelodysplasia (MDS). Our results, reported here, show that the distribution of Ha-ras alleles in myelodysplastic patients is not significantly different from that in normal individuals.     

Evolutionary relationships of human populations from an analysis of nuclear DNA polymorphisms

The genetic relationships of human populations have been studied by comparing gene frequency data for protein and blood-group loci of different populations. DNA analysis now promises to be more informative since not only do the DNA coding sequences have more variation than their corresponding proteins but, in addition, noncoding DNA sequences display more extensive polymorphism. We have now studied the frequency of a group of closely linked nuclear DNA polymorphisms (haplotypes) in the beta-globin gene cluster of normal (beta A) chromosomes of individuals from eight diverse populations. We have found that all non-African populations share a limited number of common haplotypes whereas Africans have predominantly a different haplotype not found in other populations. Genetic distance analysis based on these nuclear DNA polymorphisms indicates a major division of human populations into an African and a Eurasian group.