Genetic Archaeology

Baptismal and census records will only take us back so far in reconstructing the history of this Rowsell family. The new science of genetic archaeology can take us the rest of the way - right back to the dawn of the human family.

The DNA of all males includes a Y-chromosome that is passed down from father to son. Rarely, a harmless mutation will occur on that Y-chromosome which is then passed down, intact, exclusively to the "founder's" direct male descendants. In this way, male lines become genetically distinct over time. Modern geneticists can test for those harmless mutations ("markers"), and thereby reconstruct human origins and migrations going back throughout our 150,000-year history as anatomically modern humans.

Geneticists divide the Y-DNA phylogenetic tree into approximately 21 main branches, known as "Y-DNA haplogroups". They are classified by the letters "A to T". Each Y-DNA haplogroup has many further sub-branches (subclades), classified by numbers and letters, i.e. R1b1a, R1b1b, etc. All people living today have descended from one of these 21 main branches of the human Y-DNA "phylogenetic tree".




ROWSELL HISTORY

Paternity issues aside, all direct male descendants of John Rowsell will contain 10 distinct genetic characteristics which place us into what is known as Y-DNA Haplogroup I, Subclade I2b1. By mapping the occurrence of those 10 markers geographically in the overall human population, genetic archaeologists have reconstructed the following ancient history for this Rowsell family.

Our Y-DNA, which is passed down from a father to son, shows that all people living today shared a common male ancestor who lived in Africa. He is often termed the "Y-Chromosomal Adam".  Most people living outside Africa today are descended from a small group who migrated out of Africa into the Middle East about 40,000 years ago. The descendants of those migrants spread out in many directions, but my ancestors moved northward into Eastern Europe.

Haplogroup I

The founder of Haplogroup I lived approximately 25,000 years ago in the Balkans during the last major Ice Age.  (His ancestors had already journeyed from the Middle East into the Balkans, and are known today as Haplogroup F.)  The highest frequencies of Haplogroup I are still found in the Balkans today, near the Dinaric Mountain chain in Croatia.  Haplogroup I is strongly associated with Croat populations, namely Slavic people living in Croatia, Bosnia and Herzegovina and other nearby countries.

As shown in the above map, these ancestors continued their journey into Northern Europe as the ice sheets retreated at the end of the last major Ice Age. Today, a large portion of Scandinavian populations in the Adriatic regions, including Denmark, mainland Norway, Sweden, and Finland trace their ancestry to this Haplogroup I.  Vikings also likely descended from this line.  The presence of some, small frequencies of this haplogroup on the British Isles, France and some Celtic populations may be the result of more recent Vikings raids in these regions.

The association between Haplogroup I and Celtic culture is consistent with the parallels seen between the observed spread of Haplogroup I into Western Europe and the corresponding Celtic expansion that occurred in the mid-first millennium BC.

 

Subclade I2b1

The signature mutation ("marker") for the I2b1 subclade is known as M223 SNP. Subclade I2b1 makes up just a very small fraction of the Haplogroup I overall. In Sweden, for example, 42% of the male population is Haplogroup I, but only 5% of those men will  be from subclade I2b1. A similar trend is found throughout Europe, where I2b1 contributes only between 1 and 25% of the total pool of men from Haplogroup I.  I2b1 males are found with the highest frequency around Denmark, Germany and the Netherlands. The below map shows the areas of greatest intensity of Haplogroup I in Western Europe today, and illustrates the prevalence of M223 on the Southeastern shores of the North Sea.