• Compendium of Genetic Genealogy

Compendium of Genetic Genealogy

The Compendium is a comprehensive guide to genetic genealogy terminology, best practices, and science. – Rebekah


23andMe is a DNA testing company. Their tests are used for both personal medical risk testing and for genetic genealogy.


Aboriginal people are the indigenous people for a location. Researchers sometimes call them first peoples.


In human population genetics, admixture is the process of two or more populations interbreeding. The populations prior to admixture have been separate.

African Ancestry

African Ancestry is a direct to consumer testing company. They are located in the United States of America.

Ancestry DNA (Ancestry.com DNA)

Ancestry is a genealogy company. They also sell DNA tests for personal ethnic origins and genealogy. Their tests are based on a microarray chip.

Ancient DNA

Ancient DNA (aDNA) is the DNA of anyone who has been dead for more than 50 years. The name sounds like it should only include really old samples or pre-historic people. However, the methods used to get ancient DNA results apply to most people who have been dead for more than a few years.


Anthropology is the study of human cultures and human society. Cultural anthropology focuses on human behaviors. Physical anthropology focuses on physical artifacts of human society.


Anzick-1, Anzick Boy, is a Paleo-Indian male child. His remains were found at a Clovis Culture site. He was one of two children found in 1968, at the site in south central Montana, USA. His death and remains date to between 12,707 and 12,556 years ago.


Archaeology is the study of human history and prehistory. Researchers study the study artifacts and other physical remains.

Atlantic Modal Haplotype (AMH)

The Atlantic Modal Haplotype is a Y-chromosome DNA haplotype based on six Y-STR markers. Using those six markers it is the highest frequency haplotype in Western Europe.

Autosomal DNA 3rd Party Sites & Tools

Autosomal DNA is the DNA we get equally from both parents. Most people have autosomal DNA tested at one of the five major testing companies (23andMe, Ancestry, Family Tree DNA, MyHeritage, or Living DNA). The following are 3rd Party sites and tools.

Autosomal DNA Company Comparison Chart

Autosomal DNA is now the most used test for personal ethnic origins and recent genealogy matching. It is also the most complex method. Each of the testing companies has their own proprietary matching method.


A nucleobase, base, is a component of DNA and RNA. There are five nucleobases. They are Adenine, Cytosine, Guanine, Thymine, and Uracil.

Base pair

A base pair is two linked nucleobases. This is the basic unit of DNA. In DNA, the four bases are guanine, cytosine, adenine, and thymine. Guanine forms base pairs with cytosine. Adenine forms base pairs with thymine.


Biogeography is the study of ecosystems in relationship to species and geography over geological time. It uses practices from biology, genetics, geography, and geology.

Birger Magnusson

Birger Magnusson, the Birger Jarl, was a leader in early Sweden. He lived from about 1210 to 1266.

Buccal cell

A buccal cell is a cell from the lining in the human mouth. It is part of the body system that keeps the inside of our mouths moist. This system has a fast cell replacement time of about a day. Buccal cells are often used for DNA testing.

Cambridge Reference Sequence (CRS)

The revised Cambridge Reference Sequence is based on the first mitochondrial genome to be tested. The first version was published in 1981.


In human genetics, CCR5 is a gene on chromosome 3. It is known in popular science by the Delta 32 mutation. This mutation is a deletion of part of the CCR5 gene.

CeCe Moore

CeCe Moore is a genetic genealogist. She works as an advocate for the field, as an unknown parentage researcher, and as a forensic genealogist. She works on the TV programs Finding Your Roots and Genealogy Roadshow.

Celebrity DNA

It is increasingly common for public figures and other famous people, celebrities, to DNA test. This is often done for TV shows such as Who Do You Think You Are and Finding Your Roots.

centiMorgan (cM)

A centiMorgan is the distance between two chromosome positions. One centiMorgan is the distance where the expected average number of intervening chromosomal crossovers in a single generation is 0.01.

Cheddar Man

Cheddar man is the remains of a man who lived around 9,000 years ago in the British Isles. His remains were found in 1903.


A cousin is historically any member of your extended family. More recently, it is considered someone you share a known ancestor who is not part of your immediate family. Immediate family is your first degree relatives (parents and siblings), and your second degree relatives (grandparents, aunts, and uncles).

DNA replication

In humans DNA replication is the process of creating two copies of a DNA strand from one. It is an essential part of the cell replication process.

Dog DNA Testing Comparison Chart

Dog DNA testing is a relatively new science. Most tests currently focus on one or two genetic traits or very recent breed matching. This dog DNA Company Comparison Chart covers all major companies in the industry.


Endogamy is the social practice of only marrying within the social group. Cultures that practice endogamy have strict taboos against marriage outside of the group.


An enzyme is a something produced by a living organism that causes a chemical change. In genetics, there are replication and restriction enzymes.


Ethnicity is a shared cultural tradition. It may be based on common ancestry, culture, language, history, or nationality. Ethnicity is usually inherited from one's parents.


Exogamy is the cultural practice of marriage only outside of ones own group. This is enforced by cultural taboos. In medical and population genetics, exogamy is important because it increases the amount of genetic diversity.


A factoid is either speculation or an untested theory that is repeated enough that it is treated like a fact. In popular culture, there are many genetics factoids.

Family Tree DNA

Family Tree DNA is a direct to consumer testing company. They are located in the United States of America.

Finding Your Roots with Henry Louis Gates

Finding Your Roots with Henry Louis Gates Jr. is an American documentary style TV show. The host is historian Dr. Henry Louis Gate Jr. The first episode was shown Mar 25, 2012. So far, there have been four seasons of the program. A fifth season in 2019 is planned.

Fixation index (FST)

Fixation index is a statistic used in human population genetics. It is a measure of how alike or un-alike two or more groups of people are genetically.


Forensic science is the study of criminal and civil laws in crime investigations. Forensic research involves many fields including law, medicine, genealogy, and genetics.

Full Genomes Corporation

Full Genomes Corporation is a direct to consumer testing company. They are located in the United States of America.

Gene expression

Gene family

A gene family is a set of genes that has similar function. They often are variants of a single gene in the distant past.


Genealogy is the personal or professional study of family groups and lineages. Researchers use documents, images, and genetics as part of their studies.

Genebase Systems

Genebase is a direct to consumer testing company. They are located in Canada. They offer mtDNA and Y-DNA tests.

Genetic determinism

Genetic determinism is the belief that human and thus individual behavior is predetermined by genetics alone.

Genetic distance

Genetic distance has three meanings in human genetics and genetic genealogy. It can mean the general amount of distance between two populations. It can be specific to a comparison between two mtDNA or Y-DNA haplotypes. It can also be a measure of the size of an autosomal or X-chromosome DNA segment shared between two or more people.

Genetic drift

Genetic drift is the shift in frequency of genetic variants in a population due to random chance. This over time. It is more common in small isolated populations.

Genetic exceptionalism

Exceptionalism is the belief that something is set apart and not subject to the same set of rules. Genetic exceptionalism treats genetics as separate.

Genetic genealogist

A genetic genealogist is someone who specializes in the correct use of genetics to solve genealogy problems.

Genetic paternalism

Paternalism is acting for the good of others by taking away their right of choice. Genetic paternalism is taking away personal choices about genetic information. This is an ethical issue for medicine as well as genetic genealogy.


Genetics is part of biology. Scientists in this field study how traits are passed from parent to child. People have known since prehistoric times that living things get traits from their parents. Early farmers used this to improve crop plants and animals. They used selective breeding.


A genogram is a type of pedigree chart. It shows detailed information about the relationships between family members. It is often used in genetic counseling and psychiatry.

Glacial Maximum

A glacial maximum is the peak point in an ice age. During the peak, the ice sheets reach their greatest size and temperatures are the coldest.


Guanine is one of the four main nucleobases found in nucleic acids. It is thus part of DNA and RNA. In DNA, guanine is paired with cytosine.

Half-Identical Region (HIR)

A half-identical region (HIR) is when two people share a DNA segment. The segment matches to one of the two chromosomes for each person. This is opposed to full matching where one or both people match all of the segment on both chromosomes in their chromosome pair.


History is the study of the past as recorded in written documents. Because it relies on written records, history an a population does not begin until written records were introduced. Events before this are considered part of pre-history.

Indigenous peoples of the Americas

The indigenous peoples of the Americas are the people who lived here before the arrival of European explorers. Sometimes researchers call them pre-Columbian.

Indigenous peoples of the Americas – Genetics

The indigenous peoples of the Americas brought with them a distinctive set of genetic lineages from Eastern Eurasia. These are studied in ancient and modern DNA to expand the first people's story.

Kennewick man – Ancient DNA of North America

Kennewick Man is the remains of a man who lived in early North America. He lived about 9,000 years ago.

Living DNA

Living DNA is a direct to consumer testing company. They are located in the United Kingdom.

Markina Gora skeleton

The Markina Gora skeleton are the human remains of a Russian male. He lived around 35,000 years ago. His grave was found at the Kostenki site.


Mitosis is part of the replication process for our cells. Replication is the process by which a cell becomes two new cells.

Molecular anthropology

Molecular anthropology is the study of anthropology using molecular traits. Molecular traits include blood groups, DNA, and immune system function.

mtDNA Company Comparison Chart

The number of DNA testing companies is growing. Mitochondral DNA (mtDNA) testing for direct maternal lineages remains the most reliable way to establish evidence of a relationship between two people who share a female ancestor in the most recent fifteen generations.

mtDNA Testing for Genetic Genealogy

An mtDNA test (mitochondrial DNA test) is used for maternal genealogy. MtDNA is passed from a mother to her children. Thus, it traces a direct maternal line. Both men and women can take mtDNA tests.

Mummy Juanita

The mummy Juanita is the remains of a young Inca girl. They were frozen and naturally mummified. She was killed as part of a religious ceremony.

Nicholas II of Russia and family

Nicholas II of Russia was the last emperor of the Russian Empire. He was forced to abdicate in 1917. Later in 1918, he and his family was murdered.

On Your Knees Cave & Shuká Káa

On Your Knees Cave is the site of Native American artifacts and human bones. It is located on Prince of Wales Island. That is off the coast of southeastern Alaska.

Oseberg ship remains

The Oseberg ship is a Viking ship. It was found in a burial mound in Norway.

Ötzi the Iceman

Ötzi the Iceman is a mummy of a man who lived between 3400 and 3100 BCE. His body was found frozen in the Alps.

Oxford Ancestors

Oxford Ancestors is a direct to consumer testing company. They are located in the United Kingdom.

Pedigree chart

A pedigree chart is a diagram that shows the relationships in a family. It can be used to show cultural, genetic, and genealogical features for members of the family. Pedigree charts are used in genetics, genealogy, medicine, and psychology.


Prehistory is the part of human history before recorded writing. It begins many thousands of years ago. Because it ends with written history, the end date is different around the world.

Ramesses III

Ramesses III was a Pharaoh of Egypt. He was the son of Setnakhte and Queen Tiy-Merenese.


In human genetics recLOH is recent Loss of Heterozygosity. This is a type of variant caused by part of DNA usually including a gene is copied over an equivalent but not identical section of DNA.

Restriction enzyme

A restriction enzymes break DNA into parts. Each enzyme does this at a specific point in DNA.

Sweyn II of Denmark

Sweyn II Estridsson, King of Denmark, ruled from 1047 until his death in 1076. He was born around 1019 to Ulf Thorgilsson and Estrid Svendsdatter.

Time to the Most Recent Common Ancestor (TMRCA)


In human genetics, transcription is part of the gene expression process. In transcription, RNA polymerase reads DNA.


Tutankhamun, King Tut,was an Egyptian pharaoh. He ruled about 1332 to 1323 BCE.


The X-chromosome is one of the two human sex chromosomes. These are the chromosomes that code for sexual traits.

X-DNA Company Comparison Chart

X-chromosome DNA (X-DNA) for genealogy is usually used alongside autosomal DNA. However, its unique inheritance pattern is key to specific types of genealogy matching.


In human genetics, the Y-chromosome is the male sex chromosome. It contains most of the genes that related to male sexual anatomy.

Y-chromosome DNA haplogroup

Y-chromosome DNA (Y-DNA) Haplogroups are the branches of the male tree of humans. This human tree reaches back to the earliest people. It even reaches back before there were humans.

Y-DNA Haplogroup Projects at Family Tree DNA

Y-DNA Haplogroup projects are one of the three types of DNA projects that all Y-DNA tested men should consider joining. Most people join them after receiving their Y-DNA test results, as you need to know your tested or predicted Y-DNA haplogroup before you join.

Y-DNA Testing for Genetic Genealogy

Y-chromosome DNA, Y-DNA, testing for genetic genealogy is both the second most common type of DNA testing for genealogy and the second type of DNA test to be used in academics to study population histories.

Young Man of Byrsa

The Young Man of Byrsa or Ariche is the remains of a man who lived in Carthage in the 6th century BCE. His remains have been DNA tested.


YSeq is a direct to consumer DNA testing company. They are located in Germany.