Based on available DNA sequence data in the HLA region of 4 Mb, we review the degree of polymorphism at 39 loci of which most are involved in the immune system. The extent of nucleotide differences per silent site differs greatly from locus to locus. It is exceptionally high at classical MHC loci, intermediate at six MHC-related pseudogenes as well as at some loci in class I and II regions, and...

Predisposition to non-familial, sporadic cancer is strongly influenced by multiple tumor susceptibility genes (TSGs), each with apparently minor effects on the cancer phenotype. Sequence analysis of the human genome has yielded numerous single nucleotide polymorphisms (SNPs), raising the expectation that new low-penetrance TSGs will be identified that can be used to estimate an individuals canc...

Cytochrome P450 enzymes, especially the CYP2C subfamily, are involved in the generation of reactive oxygen species and are regarded as susceptibility factors for age-related diseases. Furthermore, the CYP2C-encoding genes are known to be highly polymorphic, with a number of variants leading to changes in enzyme activity. These observations prompted us to investigate whether allelic variation in...

Many diploid organisms undergo facultative sexual reproduction. However, little is currently known concerning the distribution of neutral genetic variation among facultative sexual organisms except in very simple cases. Understanding this distribution is important when making inferences about rates of sexual reproduction, effective population size, and demographic history. Here we extend coales...

The eating quality of cooked rice is important and determines its market price and consumer acceptance. To comprehensively describe the variation of eating quality in 183 rice germplasm accessions, we evaluated 33 eating-quality traits including amylose and protein contents, pasting properties of rice flour, and texture of cooked rice grains. All eating-quality traits varied widely in the germp...

Although organisms with linear chromosomes must solve the problem of fully replicating their chromosome ends, this chromosome configuration has emerged repeatedly during bacterial evolution and is evident in three divergent bacterial phyla. The benefit usually ascribed to this topology is the ability to boost genetic variation through increased recombination. But because numerous processes can ...

We have developed the population tube (poptube) system for sensitive detection and large-scale sampling of DNA sequence variation in several human populations of wide geographic distribution. In this methodology, genomic DNAs from five individuals in a population are PCR amplified en masse to maximize deliberately the chances of forming heteroduplexes among allelic variants. Interpopulation mix...

Allelic heterogeneity within protein electromorphs at three loci was examined in populations of deer mice (Peromyscus maniculatus) collected from five localities across North America. We used a variety of electrophoretic techniques (including several starch and acrylamide conditions, gel-sieving, and isoelectric focusing) plus heat denaturation. Of particular interest was the supernatant glutam...

BACKGROUND c-kit expression by immunohistochemistry has been utilized to identify cancer patients who can be treated with imatinib-mesylate. In gastrointestinal stromal tumors (GISTs), an activating mutation in c-kit predicts treatment response; its presence in other soft tissue tumors is unexplored. MATERIALS AND METHODS We evaluated seven cases of dedifferentiated liposarcomas (DDLS) and co...