My DNA: Where Did My Ancestors Come From? (Part 1)

"Where do I come from?" is a question we may ask ourselves. Prof. Dr. Reinhard Renneberg sent his own DNA on a journey through time to find this out.

The Genographic Project

More articles from the series:

The Genographic Project was launched as a five-year anthropological study in April 2005 by the US National Geographic Society and IBM in cooperation with the University of Arizona and Family Tree DNA. The project’s aim was to map the historical migratory movements of humankind. To this end, they collected DNA samples from over 100,000 people on all five continents.

The project was unique in that it was open to the public. For $100 (price in 2009, excluding customs and shipping costs), you could have a self-test kit delivered anywhere in the world, and you would then send a swab of your oral mucosa back to National Geographic. 

Following the analysis, the results were published anonymously in an internet database. Genetic markers on the mitochondrial DNA (mtDNA) were used to determine the degree of relationship in the maternal line and those on the Y chromosome (12 microsatellite markers and haplogroup SNPs) were used to determine the degree of relationship in the paternal line. 

In this way, each study participant learned about his or her own genetic origins and maternal and paternal lineage. By April 2009, more than 300,000 curious people had participated and on 30 August 2009, the National Geographic Channel showed a documentary called The Human Family Tree, using the results available so far.

World map of human migrations  © Genographic Project

Migrating DNA: My personal results

A month later, I received an email:

"Dear Professor Reinhard Renneberg, 
Your results are here! 
Your Y chromosome belongs to haplogroup E3b (M35)."

Wait, what are haplogroups anyway? My kind colleague Dr Roman Scholz, CEO of the company Igenea in Switzerland and Germany, explains it to the novice:

What are haplogroups?

You can think of haplogroups as large branches of the Homo sapiens family tree. A haplogroup unites people whose genetic profile is similar and who share a common ancestor. A Y chromosome haplogroup includes males who share a common ancestor in a purely paternal line. The Y chromosome is always passed from father to son.

A haplogroup of mitochondrial DNA (mtDNA) includes both males and females who have a common ancestor in a purely maternal line. All mtDNA is passed on from the mother to her children. These haplogroup branches are indicative of how populations have moved across the globe. In other words, haplogroups also define a geographical area, with older ones being larger in size and more widespread. Numerous younger subgroups are descended from them.

What are SNPs?

When determining a haplogroup, the so-called SNPs need to be analysed. SNP, say snips, is short for single nucleotide polymorphism and refers to a variation of a single base pair in a complementary DNA double strand.

SNPs are inherited and inheritable genetic variants. In contrast, a mutation is usually a newly introduced modification. Some 90% of all genetic variants are based on SNPs. They are very quick and easy to determine. SNP tests are available for mtDNA and Y chromosomes and can be used to confirm the affiliation of a person to a haplogroup. Though haplogroups do not yet play an important role from a genealogical point of view (near past up to 1,000 years), they are important from an anthropological and historical perspective (ancient and protohistoric past).

This type of analysis allows the branching of haplogroups and subgroups to be traced since our African origins and it reveals interesting facts about migratory movements of our early ancestors. The Y chromosome SNPs always carry a letter and a number as an identifier. While the letters define the laboratory that discovered this SNP, the number defines the sequence.

There is a second method to determine the haplogroup of the Y chromosome: The main haplogroup can also be examined through DYS markers by comparing the alleles. This method is correct in 99% of cases, but SNP analysis is required for 100% accuracy.

Who was our ancestral father or the "Adam" of the Y chromosome?

Admittedly, this man is not the forefather of all humans, but he is the last man historically to be related to all men living at a given time through an uninterrupted line of male-only descendants. According to modern estimates, this man lived in Africa between 60,000 and 90,000 years ago. He passed on his Y chromosome, but over the generations more and more mutations occurred that kept modifying the profile.

This is how the haplogroups developed. At the beginning of each haplogroup there is always one single ancestor, that is the first male who carried a particular mutation. Over time, the genetic family tree grew larger and became more and more complex. New SNPs emerged all the time, establishing new subgroups.

Who was our ancestral mother or the "Mitochondrial Eve"?

The mitochondrial Eve is the woman from whose mitochondrial DNA (mtDNA) emerged the mtDNA of all humans living today. Analogous to the Adam of the Y chromosome, she represents in a sense the primordial mother of all humans in the purely maternal line. About 175,000 years ago, she also lived in Africa. Numerous ancestral mothers are descended from this mitochondrial Eve, who stands at the beginning of a haplogroup and thus represents the first woman to carry this one particular mutation.

The rest of the email to me reads as follows:

"Your STRs. Below you can see the laboratory analysis results of your Y chromosome. Your DNA was examined for short tandem repeats (STRs)."

These represent repeating segments of your genome with a high mutation rate. The location of each of these markers on the Y chromosome is shown in the illustration – along with the number of repeats of each STR to its right. For example, DYS19 is a repetition of TAGA. If this sequence in your DNA was repeated twelve times at this location, we would note this as DYS19 12. Analysing the combination of these STR lengths in your Y chromosome allows geneticists to assign you to a particular haplogroup, revealing the extensive migration of your ancestors.

Y-SNPs of the Y chromosomes

In case the analysis of your STRs did not lead to any result, the Y chromosome is additionally examined for the presence of an informative single nucleotide polymorphism (SNP). These are variations in individual nucleotide bases due to mutations that enable the researcher to definitively assign you to a genetic haplogroup.

You are identified as a member of haplogroup E3b by the results of the analysis of your Y chromosome. The genetic markers that define your ancestry go back some 60,000 years to the first marker common to all non-African males, M168, and follow your lineage to the present day. They end on M35, the defining marker of haplogroup E3b."

In part 2, you can follow my specific migration route!

  1. Renneberg, Reinhard et al. (2022, in Vorbereitung): Biotechnologie für Einsteiger (6. Auflage), Springer Spektrum, Heidelberg. (Only available in German)