affected sibling pair study
a gene identification approach that looks for single nucleotide polymorphisms (SNPs) that siblings with a particular trait share, but that siblings who do not have the trait do not share.
coefficient of relatedness
the proportion of genes that two people related in a certain way share
complex trait
a phenotype that is either monogenic or polygenic, and influenced by the environment
concordance
a measure indicating the degree to which a trait is inherited; percentage of twin pairs in which both members express a trait
copy number variant
A DNA sequence present in different numbers of copies (repeats) in different individuals
empiric risk
probability that a trait will recur based upon its incidence in a population, based on observation
genome-wide association study
comparison of millions of variants (single nucleotide polymorphisms or copy number variants) that form haplotypes between people with a condition and unaffected individuals to identify parts of the genome that might contribute to a phenotype
heritability
an estimate of the proportion of phenotypic variation in a population that is due to genetic differences
homozygosity mapping
correlation of stretches of homozygous DNA base sequences in the genomes of related individuals to certain traits or disorders
incidence
the number of new cases of a disease during a certain time in a population
polygenic
a trait determined by more than one gene
polygenic risk score
a test of single base differences in several genes derived from people with a specific condition that is then used to identify people in another group who are at high risk of developing the condition
prevalence
the number of cases of a disease in a population at a particular time
single nucleotide polymorphism
a site in the DNA that has a different base in at least 1 percent of a population
