Y-Chromosome Adam is a term from population genetics for the common paternal ancestor of all men living today. For genetic genealogy, it is useful as the root of the human Y-DNA tree.
Linkage disequilibrium describes any case in population genetics where the frequency of two alleles being found together implies a non-random association. That is, the odds of both alleles happening together is not random.
Genetic genealogy DNA test kits use saliva samples to collect DNA from dead cells inside our mouths. Test kits from Ancestry.com and 23andMe use spit collection tubes while Living DNA and Family Tree DNA use swabs.
An X-match is a genetic match that shares a relevant DNA segment on the X-chromosome. Because the X-chromosome follows a different inheritance pattern than autosomal DNA, X-matches are highly significant for some genealogy applications.
The Journal of Genetic Genealogy (JoGG) is a peer reviewed journal dedicated to the topics of genetic genealogy and population genetic citizen science. Its editor in chief is Dr. Leah Larkin.
Genetic imputation is the process of determining untested genetic markers in an individual using their tested markers and haplotypes from reference samples.
A founder effect is when a small group from one population forms a second new population. Due to the small number of founders, the genetics of the new population are different from the first one.
In population genetics, a haplogroup is a group of related haplotypes. However, in genetic genealogy, a haplogroup has come to mean a branch on either the maternal or the paternal tree of humanity.
Gene by Gene is the parent company of Family Tree DNA. It's primary owners are Bennett Greenspan and Max Blankfeld.
In genetic genealogy, a DNA segment is a length of DNA on either an autosomal DNA chromosome or the X-chromosome that is shared between two or more people.