Understanding Your Y-DNA Results Contents - Genebase

GTB-DYR, VERSION 2.4, LAST UPDATED MAY 15, 2012 Downloading Y-DNA Results
Nucleotide: The basic structural unit of DNA and RNA consisting of a deoxyribose or ribose sugar, joined with a purine (A or G) or
pyrimidine (T or C) base and a phosphate group. When linked together, the chain of nucleotides form the DNA strand.
Nucleus: A membrane enclosed structure found in the central region of the cell which contains most of the cell's DNA
(chromosomes).
Organelle: Membrane bound compartments within the cell that have specific functions such as the mitochondria.
Overlapping Markers: Markers which you have tested which someone else have also tested. When comparing two or more
individuals, overlapping markers are compared.
Paternal Lineage: The direct Paternal line i.e. father's, father's, father's.... line. This line can be traced by testing an individual's Y-
DNA since Y-DNA is passed down from father to son.
Paternity Index (PI): A likelihood ratio representing a comparison of the probability that the alleged father is the biological father
versus the probability that a random man in the population is the biological father. A PI is calculated for each locus and is used to
calculate the combined paternity index and probability of paternity.
Phylogenetic Tree: A tree which shows evolutionary relationships between organisms that have a common ancestor. In human
ancestry, the Y-DNA Phylogenetic tree is constructed based on SNP markers in the Y-DNA and the mtDNA Phylogenetic tree is
constructed based on SNP markers in the mtDNA and shows how all humans descended from common Paternal and Maternal
ancestors respectively.
Polymerase Chain Reaction (PCR): Technique for amplifying specific regions of DNA by multiple cycles of DNA polymerization.
PCR is the method used by the DNA laboratory to amplify specific loci for analysis, and is capable of producing a genetic profile
from very small amounts of sample.
Polymorphism: The genetic variation between individuals or populations.
Population Genetics: The study of differences in genetic material between different populations.
Positive SNP marker: When referring to mtDNA, refers to single locations in the mtDNA which differs from CRS. If someone is
positive for 16223, that means that at location 16223 of the mtDNA, their marker differs from CRS. When referring to Y-DNA, refers
to SNP markers which are not the ancestral type.
Power of Exclusion (PE): The ability of an assay to discriminate between a real match and a non-match.
Predicted Haplogroup: In reference to Y-DNA, a Y-DNA Haplogroup that is predicted through Y-DNA STR testing but not yet
confirmed through Y-DNA SNP backbone testing. In reference to mtDNA, a mtDNA Haplogroup that is predicted through HVR1
and/or HVR2 testing but has not yet been confirmed by testing the Coding Region through mtDNA SNP backbone testing.
Prior Probability: This is a value ranging from 0 (impossible) to 1 (absolute certainty). A prior probability value of 0.5 is commonly
used.
Probability of Paternity: A statistical percentage based upon the combined paternity index and prior probability, describing the
probability that the alleged father is the biological father of the child. A 0% probability of paternity indicates a paternity exclusion and
a probability of paternity of 99.9% or greater is indicative of a paternity inclusion.
RMI (Relative Match Index): A measure of how closely your Y-DNA STR haplotype matches those of defined population groups as
compared to all other population groups in the comparison. For example, a RMI of 100 means that you are 100 times more likely to
belong to that population set as compared to the rest of the populations.
Sequencing: A laboratory process to read an entire length of DNA, usually up to 500 base pairs at a time. mtDNA HVR1, HVR2
and Coding Region Full Sequencing are tested using Sequencing technology.
Sibling Index: A statistical likelihood ratio representing a comparison of the probability that the individuals are related as siblings
(full or half) versus the probability that the individuals are unrelated. A sibling index is calculated for each locus and is used to
calculate the Combined Sibling Index.
SNP (Single Nucleotide Polymorphism): A change (mutation) in the DNA sequence involving a single nucleotide (A, C, T, or G).
SNP Test Panel: A specially selected panel of SNP markers designed for a specific purpose. Examples of SNP test panels include
the mtDNA and Y-DNA Backbone SNP Panels to confirm an individual's Haplogroup and the Subclade SNP Test Panels, designed
to provide further resolution by determining the Subclade once the Haplogroup has been confirmed.
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