What role does DNA have in family history
Genetic ancestry testing, or genetic genealogy, enables individuals interested in family history (genealogy) to discover more about their ancestors than is possible via relatives or historical evidence. Examining DNA variants may provide information about a person’s origins and the links between families. Certain patterns of genetic variation are often shared across individuals with distinct ancestries. The closer two people, families, or populations are connected, the more variation patterns they often share.
In genealogy, three forms of genetic ancestry testing are often used:
Y chromosome analysis
Variations in the Y chromosome, which is transferred solely from father to son, may be utilized to trace male lineage. Males can only be tested for the Y chromosome, since females lack the Y chromosome. Women interested in this form of genetic testing, on the other hand, sometimes enlist a male relative to undergo the test. Due to the fact that the Y chromosome is handed down in the same way as family names are in many cultures, Y chromosome testing is often used to determine if two families with the same surname are related.
Mitochondrial DNA analysis
This method of testing detects mitochondrial DNA variants. Although the majority of DNA is contained in chromosomes inside the cell nucleus, mitochondrial structures contain a minor quantity of their own DNA (known as mitochondrial DNA). Because both men and females inherit mitochondrial DNA from their mothers, this sort of testing is applicable to either sex. It contains information on the female line’s direct ancestors. Mitochondrial DNA testing is beneficial for genealogy because it maintains information on female ancestors who may have been omitted from the historical record due to the way surnames are often handed down.
Testing for single nucleotide polymorphisms
These tests examine a vast number of variants (single nucleotide polymorphisms, or SNPs) spread over an individual’s complete genome. The findings are compared to those of individuals who took the tests in order to determine a person’s ethnic origin. For instance, the pattern of SNPs may imply that a person’s ancestry is around 50% African, 25% European, 20% Asian, and 5% unknown. Genealogists utilize this sort of test because Y chromosome and mitochondrial DNA test results, which only indicate specific ancestral lines, do not accurately reflect an individual’s total ethnic heritage.
Genetic ancestry testing is not without drawbacks. Because test providers compare individuals’ test results to disparate databases of past tests, ethnicity estimates may vary across providers. Additionally, since the majority of human societies have traveled often throughout history and intermarried with neighboring groups, ethnicity estimations based on DNA testing may vary from an individual’s expectations. In ethnic groups with a limited range of genetic diversity owing to their size and history, the majority of members share a large number of SNPs, and it may be difficult to identify individuals with a shared ancestor, such as fourth cousins, from the group as a whole.
Numerous corporations and organizations provide genetic ancestry testing. The majority of firms provide online forums and other services that enable individuals who have been tested to share and debate their findings with others, which may reveal previously undisclosed ties. On a bigger scale, scientists may utilize the combined genetic ancestry test results of a large number of individuals to investigate the history of populations as they evolved, moved, and mingled with other groups.
To learn more about genetic ancestry testing, see the University of Utah’s molecular genealogy video lessons.
The International Society of Genetic Genealogy advocates DNA testing as a tool for genealogical research.
Human origins and ancestry are discussed at the National Human Genome Research Institute.
In collaboration with the National Institutes of Health
GeneReviews: Genetics Professional Resources—National Institutes of Health Direct-to-Consumer Genetic Testing
The Technology Museum of Innovation explains how ancestry testing works.
The exhibit ‘Genome: Unlocking Life’s Code’ at the Smithsonian National Museum of Natural History explores genetic ancestry testing. Additionally, the exhibit addresses the African Diaspora and its impact on hereditary and genealogical practices.
