Genetic genealogists use DNA testing to help solve family history mysteries and close cold cases. They use autosomal, Y chromosome, and mitochondrial (mtDNA) tests.
MtDNA is found in the mitochondria of cells. Only females can pass this DNA to their descendants. YDNA is passed to males from their fathers.
Role of DNA in Ancestral Roots
In its most common form, genetic genealogy involves individuals testing their DNA and conducting traditional genealogical research to discover long-lost family members. It has become more popular in recent years due to improved DNA testing technology and the availability of home test kits.
Using publicly available genetic genealogy databases, crime scene DNA from an unknown suspect can be uploaded and compared to other profiles. If a match is found, it will indicate which branch of the family tree that person belongs to based on their shared DNA.
This type of forensic DNA testing has been successful in identifying a number of unidentified murders, rapes and other violent crimes. It is also being used to identify missing people and bring families closure.
Genetic Genealogy and DNA Testing
Genetic genealogy, which combines DNA analysis with traditional historical and genealogical research, can help break through brick walls for those conducting family history research. For forensic investigators, it provides tools to identify missing persons and solve cold cases.
The forensic applications of genetic genealogy grew out of the direct-to-consumer DNA testing craze that took hold a decade ago, when companies like 23andMe and Ancestry offered customers an opportunity to spit into tubes and receive information on their ethnicity, medical risks and family connections.
The same technology can be used in a forensic context to match crime scene DNA with profiles in public databases, such as GEDmatch. A close genetic match will provide a starting point for investigators as they build out the family tree.
Y DNA and Paternal Genealogy
Men have a very different DNA than women, so Y-DNA testing can reveal their direct paternal lineage back hundreds or even thousands of years. Y-DNA tests look at a number of repeating sequences called STR markers on the Y chromosome. These marker values are unique to each male and can be used in surname or geographic projects to compare with those of other men. Occasional (harmless) mutations can also help define particular branches.
Because only genetic males have a Y chromosome, they are the only ones who can take a Y-DNA test. However, females who wish to explore their paternal ancestry can sponsor their father, brother or paternal uncle for a Y-DNA test. Many of the companies offering Y-DNA testing include a Family Finder feature in their results, which can connect you with living relatives who share your paternal haplogroup.
mtDNA in Maternal Ancestry
Maternal lineage DNA, analyzed by mtDNA tests, can reveal female family connections that aren’t possible to find through paternal testing or other autosomal DNA tests. The mtDNA of living people doesn’t change, so mtDNA tests can provide accurate genetic markers to trace maternal ancestral lines.
Until recently, researchers believed that mtDNA was transferred to daughters through processes within the egg cells that engulfed paternal mitochondria after sperm penetrated an egg. But now it’s thought that mtDNA can actually pass from mother to daughter even without a penetration event.
Several companies offer mtDNA tests. Some, like 23andMe, examine only the HVR1 and HVR2 regions of mtDNA, while others, such as Family Tree DNA, xet nghiem adn ha noi test for the entire mtDNA sequence and provide cousin matching. These tests can help you locate your maternal haplogroup and identify the general areas of the world from which your ancestors originated.
Autosomal DNA Testing for Family Connections
DNA testing can help an individual discover his or her genetic connections to a variety of ancestral groups. Autosomal DNA tests can reveal potential relatives on either the maternal or paternal side of the family tree.
In addition to finding distant ancestors, these tests can also provide insight into the geographic region where your ancestors originated. These regions are determined by the frequencies of specific DNA variants in reference populations worldwide.
Another popular application of DNA testing is to identify unidentified human remains. In this application, investigators extract DNA from crime scene samples and match it with public DNA databases such as GEDmatch. A successful match can help investigators construct a family tree and identify the suspect. The thematic analysis found that participants’ notions of identity were often challenged by unexpected DNA test results. In particular, the discovery of biological kinship prompted a re-negotiation of gender, racial and familial identities.