Earliest Known Ancestor (EKA)
Pretty self explanatory. Referring to that of a particular lineage.
Family Tree DNA Time Predictor (FTDNA TIP)
"A program used to calculate estimates of Time to the Most Recent Common Ancestor (TMRCA). It is the world's first calculator that incorporates mutation rates specific to each marker. This greatly increases the power and precision of estimates." *
Genetic Distance
"The number of differences, or mutations, between two sets of results. A genetic distance of zero means there are no differences in the results being compared against one another (exact match)." *
Haplogroup
"A genetic population group associated with early human migrations and which can today be associated with a geographic region. It is important to note that even though female and male haplogroups may have the same letters, their definitions are different." *
Haplotype
"One person's set of values for the markers that have been tested. Two individuals that match exactly on all markers have the same haplotype." *
Most Recent Common Ancestor (MRCA)
"The ancestor shared most recently between two individuals." *
Time to the Most Recent Common Ancestor (TMRCA)
The amount of time or number of generations since individuals have shared a common ancestor. Since mutations occur at random, the estimate of the TMRCA is not an exact number (i.e., 7 generations), but rather a probability distribution. As more information is compared, the TMRCA estimate becomes more refined.
Western Atlantic Modal Haplotype (WAMH)
"The most common Y-DNA haplotypes found in Europe’s most common Y-DNA haplogroup, R1b."
Y-Chromosome
One of the two sex chromosomes, X and Y. The Y-chromosome passes down from father to son. Females do not receive it. The fact that the Y-chromosome goes down the paternal line makes it valuable for genealogy studies, since it typically follows a surname line." *
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* All definitions in quotes are from Family Tree DNA.