Legend & Glossary

Definitions of genetic genealogy terms used throughout this encyclopedia.

Genetics

Haplogroup Wikipedia ↗

A group of similar haplotypes that share a common ancestor with a single nucleotide polymorphism (SNP) mutation. Haplogroups are used to trace deep ancestry on the paternal (Y-DNA) or maternal (mtDNA) lines.

Y-DNA Wikipedia ↗

The Y chromosome, passed from father to son virtually unchanged (except for rare mutations). Y-DNA analysis traces direct paternal lineage and is used to assign paternal haplogroups.

mtDNA Wikipedia ↗

Mitochondrial DNA, inherited exclusively through the maternal line. Because it is passed from mother to all children (but only daughters pass it on further), it traces direct maternal ancestry.

SNP (Single Nucleotide Polymorphism) Wikipedia ↗

A variation in a single nucleotide at a specific position in the genome. SNPs define the boundaries between haplogroups — when a new mutation occurs, it marks the beginning of a new branch in the phylogenetic tree.

STR (Short Tandem Repeat) Wikipedia ↗

Repeating sequences of DNA used to distinguish between closely related lineages within a haplogroup. STRs mutate faster than SNPs and are used in genealogical DNA testing to find recent relatives.

Phylogenetic Tree Wikipedia ↗

A diagram representing evolutionary relationships among groups of organisms or, in this context, among human lineages. Each branch point represents a common ancestor.

MRCA (Most Recent Common Ancestor) Wikipedia ↗

The most recent individual from whom all members of a group are descended. In haplogroup context, the MRCA date represents when the founding mutation occurred.

Subclade Wikipedia ↗

A lineage nested within a larger haplogroup clade, defined by additional downstream mutations. For example, R1a-Z93 is a subclade of R1a.

Autosomal DNA Wikipedia ↗

DNA from the 22 non-sex chromosomes, inherited from both parents. Autosomal DNA tests can reveal ethnicity percentages and match relatives up to 5–6 generations back.

Haplotype Wikipedia ↗

A set of DNA variations (polymorphisms) that tend to be inherited together as a unit. A haplogroup is a group of related haplotypes sharing a common ancestral origin.

Ancient DNA (aDNA) Wikipedia ↗

DNA recovered from archaeological remains such as bones or teeth. Ancient DNA studies have dramatically reshaped our understanding of haplogroup migrations and prehistory.

Population Genetics Wikipedia ↗

The study of genetic variation within and between populations, including allele frequencies, mutations, and evolutionary forces such as drift and selection.

Genetic Drift Wikipedia ↗

Random fluctuations in gene frequencies within a population, especially pronounced in small or bottlenecked populations. Can cause a haplogroup to rise or fall in frequency by chance alone.

Founder Effect Wikipedia ↗

The loss of genetic variation when a new population is established from a small group. Explains why some haplogroups are extremely common in isolated populations.

Genealogy

Patrilineal Wikipedia ↗

Descent or kinship traced through the male (father's) line. Y-DNA haplogroups are patrilineal markers.

Matrilineal Wikipedia ↗

Descent or kinship traced through the female (mother's) line. mtDNA haplogroups are matrilineal markers.

Ru Wikipedia ↗

In Kazakh and some other Turkic traditions, a ru (also spelled ruw or род) is a patrilineal sub-clan or lineage group within a larger tribe or zhuz. Members of the same ru consider themselves to have a common male ancestor.

Anthropology

Zhuz Wikipedia ↗

One of three major tribal confederations (Senior, Middle, Junior) within Kazakh society. Each zhuz contains multiple tribes, which in turn contain clans and ru lineages.

Steppe Ancestry Wikipedia ↗

Genetic ancestry associated with Bronze Age pastoralists from the Pontic-Caspian steppe (modern Ukraine/Russia). Heavily associated with haplogroups R1a and R1b and the spread of Indo-European languages.

Statistics

Sample Size (n=) Wikipedia ↗

In frequency statistics, n refers to the number of individuals tested. Larger sample sizes produce more reliable frequency estimates.

Frequency Wikipedia ↗

The proportion of individuals in a population carrying a particular haplogroup, expressed as a percentage. e.g., 'R1a is found in 57% of Poles' means 57 out of 100 Polish men carry R1a.