Genography - The study and practice of making maps based on genetic information. Genography builds on the premise that history can be modeled in ways that communicate genetic information effectively.
TMRCA - Time to most recent common ancestor. For any set of genetic records, an approximate number of years in the past that a common ancestor existed for that set. Estimates are based on DNA test results and established mutation rates.
DMRCA - Distance to most recent common ancestor. The distance is calculated using the TMRCA multiplied by the Neolithic Migration Rate (1.2 km/yr is typical for continental Europe).
MDKPA - Most distant known paternal ancestor. Self-reported paternal origins as a result of genealogical research.
STR (Short Tandem Repeats, aka microsatellites) - A short sequences of base pairs that repeat. These repeats are found in autosomal, y and x DNA. You may have heard the term CODIS if you watch Crime/Drama shows on television. CODIS is the FBI’s Combined DNA Index System (more acronyms). When DNA is collected for CODIS, they typically test for 13 STR markers across the autosomes. When you have a yDNA STR test done, genetic genealogy companies test for up to 111 STR markers only on the Y chromosome.
SNP (Single nucleotide polymorphism, pronounced snip) - Within the 3 billion base pairs of our DNA there are variations (normally occurring mutations), where one base pair has been replaced with another base pair. As an example, it was adenine (A) and now its guanine (G). This is a single nucleotide polymorphism or SNP (pronounced snip). There are over 15 million SNPs in our DNA. Once a SNP occurs, it is usually permanent in the population. The farther back in time that the SNP occurred, the more people will have that particular mutation. To be considered a SNP, it has to exist in greater than 1% of the population. They are found in both the coding and non-coding regions of our DNA. In the coding regions, SNPs are often markers for genes.
DNA - We have DNA in every cell except the red blood cells. Inside the nucleus of our cells, we have 46 chromosomes or 23 pairs (nuclear DNA). One set of 23 comes from dad and one set comes from mom. If we took the tightly coiled DNA from one cell and stretched it out it would be about six feet long. In that six-foot double helix from one cell, there are over 3 billion base pairs. If you picture our double helix DNA as a twisted ladder, each rung is a base pair made up from four nucleotides (DNA building blocks). The rungs are made from either an adenine-thymine rung or a cytosine-guanine rung.
Genes - DNA is divided into coding regions (genes that define proteins for such things as eye color) and non-coding regions (sometimes called junk DNA). The coding region that defines us is less than 2% of our overall DNA and within that, there are less than 25,000 genes. A gene is a sequence of nucleotides averaging about 23,000 base pairs.
TribeMapper® - Your tribe has left genetic footprints through the ages. The TribeMapper Report will map your DNA and haplotype across time and geography, connecting you to a rich history.