are detectable variations occurring at a single genetic locus
Single Nucleotide Polymorphism. The alleles have a frequency of at least 1% in the general population.
short tandem repeats such as CA (Eg CACACACA or CACA). These occur within and outside of genes. These polymorphisms like SNPs can be used as genetic markers in linkage and association studies.
functional genetic alteration
Linkage Disequilibrium (LD)
occurs when an allele is associated with the disease susceptibility allele, such that these two alleles are inherited together over several generations in the population. Usually the two alleles lie in close proximity to each other (<60kb).
Combination of alleles of genetic markers in linkage disequilibrium. These are constructed statistically or observed by re-sequencing stretches of DNA. Statistically constructed haplotypes provide advantage of capturing greater genetic information at a locus in association studies. r2: is the statistic describing correlation between independent makers i.e their likelihood of being inherited together.
The relationship between marker and disease
The tracing of a mutation to a single or limited number of meiotic event(s) early in the course of evolution of a population.
A unit of genetic distance named after the Geneticist Thomas Hunt Morgan. One centimorgan (cM) is defined as the genetic distance between two loci with a statistical recombination frequency of 1%. The number of base-pairs it corresponds to varies widely across the genome. A recombination event occurs during meiosis (therefore its correlation with generations).