Genetic Genealogy 101 Part 2: Useful Terms 1

Words are important.  Sometimes if you don’t know the vocabulary you need to know for a particular situation you can get very, very frustrated.  If you are new to genetic genealogy here are a few (not all) of the words you should be familiar with.  Some of them may jog memories of high school biology class.  Others you may have already seen and guessed their meanings.  Hopefully the list will be useful to you!

Useful Genetic Terminology:

Allele: specific form of a gene, one of multiple possibilities.  In genetic genealogy used as the reference for a marker.

Chromosomes: structure in the cell where genes are located.

DNA (Deoxyribonucleic acid): a molecule that contains the genetic instructions for living organisms.

Gene: a unit of heredity in living organisms.  One gene may have multiple forms, or alleles, defined by different DNA sequences.

Genome: the collection of genes in an organism

Locus: physical location of an allele on the chromosome.

Marker: the specific place on a chromosome with two or more forms.  The inheritance of it can be followed through each generation.

Useful Genetic Genealogy Terminology:

Haplogroup: genetic population who share a common ancestor on the paternal or maternal line with similar SNP mutations.

Haplotype: the set of numbers that make up your Y-Chromosome or mtDNA results.

MRCA: Most Recent Common Ancestor

Phylo-tree: Phylogenetic Tree is the reference for diagrams that show all the haplogroups.

Proxy: the contact person for the DNA test if not the person taking the test.

SNP: Single Nucleotide Polymorphism, this test confirms you haplogroup by identifying if it has mutated from the ancestral state.

STR: Short Tandem Repeat, the number of repeats for a base pair sequence which then determine the marker value.

Sub-clade: an offshoot branch of the phylo-tree or a reference to deep clade testing.

In Part 3 I will tell you about the tests and testing companies.

About Shannon Combs Bennett

Shannon Combs-Bennett, owner of T2 Family History, is a speaker and author based out of Virginia. She enjoys teaching about a wide range of topics from DNA to methodology. Currently Shannon is the Creative Director for The In-Depth Genealogist. You can learn more about her at

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