Table 1.

Definitions of common genetics terminology

Epigenetic effects	Changes in gene expression caused by factors (e.g., methylation affecting gene transcription) other than variation in DNA sequence
Epistatic effects	Gene interactions that can affect phenotypes
Single Nucleotide Polymorphism (SNP)	A small genetic variation in the DNA sequence. The four nucleotide adenine (A), cytosine (C), thymine (T), and guanine (G) represent the building block of the genetic code. A SNP occurs when a single nucleotide (e.g., C) replaces another nucleotide in a given location (e.g., G). For example, AGTTA is replaced by ACTTA
Variable Number of Tandem Repeats (VNTR)	A VNTR is a short nucleotide sequence that is organized into clusters of tandem repeats (e.g., ATGCC, ATGCC, ATGCC).