Aboriginal. Relating to a group of people indigenous to a geographic region; the original inhabitants of a region.
Admixture. Of mixed ancestry or mixed origins.
Ancestral signature. The oldest known or hypothesized haplotype for a particular lineage. See also: modal haplotype
Anthrogenealogy. The study of human origins, recent and distant, using DNA testing and genealogical methods.
Anthropology. The study of humans, particularly in terms of origin and culture.
Cambridge Reference Sequence (CRS). The mitochondrial DNA first sequenced in 1981 which is used as a basis for comparison with mtDNA test results.
Coding region. A region of DNA which contains genes.
Cohanim Modal Haplotype. The Y-DNA haplotype most commonly found among males with an oral tradition of Cohen ancestry.
Cohen. The Hebrew word for priest which refers to a direct male descendant of Aaron, the brother of Moses; plural: Cohanim.
Convergence. The process of two unrelated or less related lineages changing over time to resemble one another.
Family Tree DNA Time Predictor (FTDNATiPTM). 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.
Genealogical Data Communication (GEDCOM). A type of file format used by genealogical software to make your family tree. You can upload your GEDCOM file to your Family Tree DNA personal page as well as Ysearch or mitosearch.
Genealogy. The study of family history.
Generation. The number of years between the birth of the parents and the birth of their children. Different studies use different numbers of years per generation. At Family Tree DNA we use 25 years.
Genetic cousins. Individuals whose Y-DNA or mtDNA test results match one another.
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).
Genetics. The study of genes and heredity; the study of DNA.
Genome. The entire complement of genetic material in a chromosome set. The human genome is composed of 46 chromosomes, with a total of 3 billion base pairs.
Genotype. The genetic makeup of an individual organism.
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.
Heredity. The transmission of genetic material from parents to offspring.
Human Genome Organization (HUGO). The entity to which, among other things, scientists submit new markers for DYS number assignment.
Hypervariable Region (HVR). One of two regions commonly used in mitochondrial DNA tests which does not code for any known function.
Junk DNA. Stretches of DNA that do not code for genes, also called non-coding DNA. Most of the genome consists of non-coding DNA, and was therefore long thought to be 'junk.' Scientists have found that in addition to containing markers that are helpful for genetic genealogy, parts of these non-coding regions have regulatory and other functions.
Marker. A physical location (locus) on the chromosome. DNASOA offers 3 levels of Y-DNA testing: 12-marker, 25-marker and 37-marker.
Meiosis. The stage in which sperm and egg cells are formed. It is during this process that the autosomal chromosomes recombine and mutations occur.
Mitochondrial DNA (mtDNA). The genetic material found in mitochondria. It is passed down from females to both sons and daughters, but sons do not pass down their mother's mtDNA to their children.
Modal haplotype. The most common result for each marker tested in a group of results. See also: ancestral signature.
Most Recent Common Ancestor (MRCA). The ancestor shared most recently between two individuals.
Mutation. A heritable change that occurs in genetic material. It may lead to a different number of repeats of a certain sequence or a change in one of the bases in a sequence.
Mutation rate. The frequency with which random mutations occur.
Recombination. An event occurring during meiosis - the formation of sperm and egg cells. One chromosome from the mother and the other from the father break and trade segments with one another.
Sex chromosome. The X- or Y-chromosome. Normally males have one X and one Y and females have two Xs.
Surname. A last name or family name traditionally passed down from father to son.
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.
Transmission event. The passage of genetic material from one generation to the next.
Western Atlantic Modal Haplotype (WAMH). The most common Y-DNA haplotypes found in Europe's most common Y-DNA haplogroup, R1b.
X-chromosome. One of the two sex chromosomes, X and Y. X is the sex chromosome that is present in both sexes: singly in males and doubly in females.
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.
Y-DNA phylogenetic tree. A graphic representation of the Y-DNA haplogroups according to the YCC classification. Haplogroup names and major clades are labeled and mutation names are given along the branches of the trees.