Novel Variant

For FamilyTreeDNA, a novel variant is a difference on a person's Big Y test from the reference sequence that has not been before seen. Novel variants may or may not be unique to an individual [...]

No Call

A no call occurs when a particular single nucleotide polymorphism (SNP) being analyzed has insufficient data to be confidently given a genotype value.


A null value is when there has been a mutation that prevents a reading for a  Y-chromosome Short Tandem Repeat (STR) from being obtainable. It may be an actual deletion of the entire STR. It may also be caused by [...]


The membrane-bound organelle containing the chromosomes.


Nucleotides are structural components of our genetic code. Each nucleotide is composed of one base plus a sugar molecule and a phosphate molecule. The bases are adenine, thymine, guanine, and cytosine, normally represented as A, [...]

Nucleic Acids

Nucleic acids are the basic components of our genetic code. DNA is made up of four types of nucleic acids: adenine (A), cytosine (C), guanine (G), and thymine (T).