ABack to top allele - Alternative forms of a gene or polymorphism. See also: SNP, gene.
major allele - The more common form of a SNP.
minor allele - The less common form of a SNP.
DBack to top D-prime - Lewontin's D-prime, a measure of the covariance of allele counts for two SNPs, under the assumption of Hardy-Weinberg equilibrium.
DNA - Deoxyribonucleic acid. DNA molecules carry the genetic information necessary for the organization and functioning of most living cells and control the inheritance of characteristics. See also: gene, RNA, nucleotide.
EBack to top ethnicity - Ascertained at four follow-ups (ages 11, 16, 33 and 42 years) using different definitions and informants. The small number of cohort members with inconsistent ethnic information have been grouped seperately.
GBack to top gene - The segment of DNA on a chromosome that contains the information necessary to make a protein. See also: DNA, genome, allele.
genome - All the genetic material in the chromosomes of a particular organism. See also: gene.
genotype - The specific genetic makeup of an organism, as contrasted with the actual characteristics of an organism (phenotype). See also: phenotype.
HBack to top Hardy-Weinberg equilibrium - The distribution of genotypes follows the pattern expected from the allele frequencies. This indicates no selective advantage or disadvantage from posessing any particular genotype. See also: D' (H-W), r² (H-W).
Hardy-Weinberg p value - Exact significance test of the Hardy-Weinberg assumption, derived using the genhw and hwsnp commands in Stata(TM), contributed by Mario Cleves.
HLA - HLA (human leukocyte antigens) are proteins found in the membranes of nearly every cell in the body. HLA antigens are the major determinants used by the body's immune system for recognition and differentiation of self from non-self (foreign substances).
LBack to top linkage disequilibrium - Where alleles at different positions occur together more often than would be expected under random assortment.
nucleotide - A building block of DNA and RNA, consisting of a nitrogenous base, a five-carbon sugar, and a phosphate group. Together, the nucleotides form codons (groups of three nucleotides), which when strung together form genes. See also: DNA, RNA.
PBack to top p (1 d.f.) - 1 d.f. significance test for association between mean and number of minor alleles. See also: p (2 d.f.).
p (2 d.f.) - 2 d.f. significance test for difference between means. See also: p (1 d.f.).
parental survival - Last ascertained at the 41/42-year interview follow-up (1999-2000).
phenotype - An observable or measurable trait or disease. See also: genotype.
position - Positional information in this database is derived from EntrezSNP (dbSNP release 127) where available, or otherwise from the position specified by the depositor (which may be from an earlier version of dbSNP).
RBack to top r-squared - Square of Pearson's correlation between the presence of minor alleles for each of two SNPs, under the assumption of Hardy-Weinberg equilibrium.
region - Place of residence of cohort member at the time of the blood collection, classified to 1958 regional boundaries.
regional variation - Tested by chi-square (11df) on allele counts for each of 12 regions. Maps show as "significant" any individual region where the regional allele frequency lies outside the 95% confidence interval for the expected frequency in that region, if the national average allele frequency applied.
reproducibility - Blind replicates were included in the plates of cell-line DNA (but not early issues of directly extracted DNA). Each replicated specimen appeared once on each of two different plates of DNA: 12 pairs per 1000 DNA specimens. Incomplete data indicates one or more failed test results from the replicate pair.
RNA - A single-stranded nucleic acid made up of nucleotides. RNA is involved in the transcription of genetic information; the information encoded in DNA is translated into messenger RNA (mRNA), which controls the synthesis of new proteins. See also: DNA, nucleotide.
SNP - Single Nucleotide Polymorphism: Differences between individuals (polymorphism) of individual bases within a nucleotide. See also: allele.
strand - Polymorphisms may be defined on either the forward or reverse strand of DNA. Genotypes from the Illumina HumanHap550 platform are coded to the "top" strand, which may be either forward or reverse, as described in http://www.illumina.com/downloads/TOPBOT_technote27Jun06.pdf
VBack to top % variance (1 d.f.) - Percentage of phenotypic variance explained by additive effect of each allele in 1 d.f. regression model. See also: % variance (2 d.f.).
% variance (2 d.f.) - Percentage of phenotypic variance explained by genotype in 2 d.f. ANOVA model. See also: % variance (1 d.f.).
variant - Includes SNPs plus other forms of genetic variation, including insertion/deletion polymorphisms (INDEL), repeat sequences (repeat) and HLA molecules.
