Long-Read DNA Sequencing
Definition
A genomic variant is a difference that is present at a specific location in one genome compared to another. The most common type of genomic variant is the difference of one nucleotide (or base) in the DNA sequence, which is known as single-nucleotide variants (or SNVs). Genomic variants can also involve multiple nucleotides, such as duplications, deletions, and inversions. Genomic variants contribute to the variation of traits seen in living organizing, including traits related to health and disease.
Narration
Most of the variants in the human genome have been around for a very long time and have been passed from generation to generation for hundreds of thousands of years. In fact, nearly millions of variants described to date have no biological effect. If a SNV appears in 1% of the population, it is known as a single nucleotide polymorphism (SNP).While people often use the word “mutation” to refer to genomic variants, a true mutation event is when a new variant appears by chance or because of DNA damage. Geneticists recognized that using the term “mutation” might lead people to think that all DNA changes are harmful or cause diseases. Researchers use the term “variant” as a more neutral word for these genetic differences, whether they be beneficial, harmful or neutral.
