Table 1.

Glossary of Statistical Genetics Terms

Term	Definition
Allele	One member of a series of different forms of a gene
Association study	The use of case-control, cohort, or even family data to statistically relate genetic variations to a disease/phenotype
Chromosome	A singular, physical piece of DNA, which can contain many genes and regulatory elements
Epistasis	Gene-gene interaction; as a deviation from additivity in the effect of alleles at different loci with respect to their contribution to a phenotype
Gene	A heritable unit; a region of genomic sequence which is associated with regulatory, transcribed, and/or other functional regions
Genotype	Specific allele combinations for an individual
Genotyping	The experimental determination of sequence variations
Linkage study	The use of genotype and phenotype information from multiple biologically-related family members to determine whether a chromosomal region is preferentially inherited by offspring with the trait of interest
Locus	A fixed position on a chromosome
Mendelian disease	A genetic disease that is caused by a single locus, and displays a pattern of inheritance in line with Mendel's Laws
Phenotype	A measurable trait for an individual
Pedigree	Multiple biologically-related individuals with known familial relationships
Single Nucleotide Polymorphism (SNP)	A DNA sequence variation; the smallest unit of variation in the genome