Jeffrey Tze-Fei Wong

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We describe the Phase II HapMap, which characterizes over 3.1 million human single nucleotide polymorphisms (SNPs) genotyped in 270 individuals from four geographically diverse populations and includes 25-35% of common SNP variation in the populations surveyed. The map is estimated to capture untyped common variation with an average maximum r2 of between(More)
With the advent of dense maps of human genetic variation, it is now possible to detect positive natural selection across the human genome. Here we report an analysis of over 3 million polymorphisms from the International HapMap Project Phase 2 (HapMap2). We used 'long-range haplotype' methods, which were developed to identify alleles segregating in a(More)
The coevolution theory of the genetic code, which postulates that prebiotic synthesis was an inadequate source of all twenty protein amino acids, and therefore some of them had to be derived from the coevolving pathways of amino acid biosynthesis, has been assessed in the light of the discoveries of the past three decades. Its four fundamental tenets(More)
The difficulty in explaining the origin of genetic coding centres on the need to identify selective advantages that could account for the synthesis of peptidyl-tRNA, the essential intermediate in genetically programmed translation. It is resolved by a recognition of the functional advantages derivable from the post-transcriptional addition of peptide(More)
This study tracks the rise, evolution and post-evolution of the genetic information system through emergence of life. The major stages traversed include prebiotic synthesis, functional RNA selection by metabolite, RNA World, peptidated RNA world, co-evolution of genetic code and amino acid biosynthesis, last universal common ancestor, Darwinian evolution(More)
The allocation of codons in the genetic code makes possible a moderate minimization of the chemical distances between pairs of neighboring amino acids in the code. However, the code is neither a global nor a local optimum with respect to distance minimization. These findings do not support the physicochemical postulate that distance minimization was a major(More)
The search for novel anxiolytics devoid of undesirable side-effects typical of classical benzodiazepines (BDZs) has been intense, and flavonoids, as a relative new class of ligands, have been shown to possess anxiolytic effects in vivo. The present study evaluated the pharmacological properties of a naturally occurring monoflavonoid,(More)
Bacillus subtilis strain QB928, a tryptophan-auxotroph, was serially mutated to yield strain HR15. For QB928, tryptophan functioned as a competent amino acid and 4-fluorotryptophan as merely an inferior analogue. For HR15, these roles were reversed. The tryptophan/4-fluorotryptophan growth ratio decreased by a factor of 2 X 10(4) in the transition from(More)
Twenty different lines of polyphasic evidence obtained from tRNA and protein sequences, anticodon usages, gene contents, metabolism and geochemistry have made possible the identification of a Last Universal Common Ancestor (LUCA) phylogenetically located proximal to the hyperthermophilic methanogenic archaeon Methanopyrus. Combined with analysis of(More)