|Glossary|

Popular Scientific Terms
Term Definition
Admixture: Admixture tests provide an estimate of overall continental genetic ancestry (European, Native American, and West African).
Allele: One of the variant forms of a gene at a particular locus, or location, on a chromosome. Different alleles produce variation in inherited characteristics such as hair color or blood type. (Source: www.genome.gov)
Ancestry: The lineage from which a person is descended, especially if more remote than a grandparent.
Chromosome: One of the threadlike “packages” of genes and other DNA in the nucleus of a cell. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all (44 autosomes and two sex chromosomes). Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers. (Source: www.genome.gov)
DNA: Deoxyribonucleic acid (DNA) is the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms. (Source: www.genome.gov)
Gene: The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein. (Source: www.genome.gov)
Genome: All the DNA contained in an organism or a cell, which includes both the chromosomes within the nucleus and the DNA in mitochondria. (Source: www.genome.gov)
Genotype: The genetic identity of an individual that does not show as outward characteristics. (Source: www.genome.gov)
Haplogroup: A large group of haplotypes that can be used to define genetic populations and are often geographically oriented.
Haplotype: A set of closely related polymorphisms that are inherited as a unit. A haplotype can be considered a DNA signature of a paternal lineage. Haplotypes are often used to compare different populations.
Lineage: The descendants of one individual. Each of us has many lineages that make up who we are. Our two parents represent two lineages. Our four grandparents represent four lineages. Our eight great-grandparents represent eight lineages. The number of lineages increases exponentially with each generation.
Marker: A segment of DNA with an identifiable physical location on a chromosome whose inheritance can be followed. (Source: www.genome.gov)
Maternal ancestry: The descendants of the females on the mother’s side of a family.
Maternal lineage: The line of a family represented by a mother, grandmother, great-grandmother, great great-grandmother and so on. The maternal lineage includes all males and females that descend directly from a woman on the line.
Mitochondrial DNA (mtDNA): The genetic material of the mitochondria, the organelles that generate energy for the cell. Mitochondrial DNA is passed down from the mother to all her children, both sons and daughters.
Paternal ancestry: The descendants of the males on the father’s side of a family.
Paternal lineage: The male line of a family represented by a father, grandfather, great-grandfather, great great-grandfather and so on. Traditionally, the paternal lineage follows the father’s last name.
Phenotype: The observable traits or characteristics of an organism, for example, hair color, weight, or the presence or absence of a disease. Phenotypic traits are not necessarily genetic. (Source: www.genome.gov)
Polymorphism: A common variation in the sequence of DNA among individuals. (Source: www.genome.gov)
Sequence: A succession of letters representing the primary structure of a DNA strand. The possible letters are A, C, T, and G, representing the four chemical components of DNA – adenine, cytosine, thymine and guanine.
SNP (single nucleotide polymorphism): Common, but minute, variations that occur in human DNA at a frequency of one every 1,000 bases. These variations can be used to track inheritance in families. SNP is pronounced “snip.” (Source: www.genome.gov)
Trait: A genetically inherited feature of an organism. See phenotype.
YAP (y alu polymorphism): An insertion/deletion polymorphism usually found in African Y-chromosomes.
Y-chromosome: A sex chromosome normal males carry one Y- and one X-chromosome. The Y-chromosome determines maleness. Males inherit the Y-chromosome from the father.