Cryan/Crehan/Crean YDNA Study by Caoimhghin O Croidheain


    YDNA Testing 

  Y-DNA passes from father to son relatively unchanged, with only small, intermittent mutations over the centuries. Because Y-DNA is so stable, it can provide solid, genealogically relevant information about a person’s paternal line. For Y-DNA testing, there must be an unbroken father-to-son line to the ancestor about whom one wants information. Since women do not have a Y chromosome and receive no Y-DNA to pass on, a Y-DNA line can “daughter out” when a father only has daughters, or may disappear entirely when an only son dies without children. YDNA testing, as seen in the image, only reads the male line going back thousands of years. Unlike the autosomal DNA tests provided by commercial DNA companies like Ancestry or My Heritage that read each family branch, the DNA often times only being good for a few hundred years. 



We are trying to learn more about the early history of the Cryan/Crehan/Crean surnames. The best way to do this is through the test for biological males: Y-DNA. With the Y-DNA test we can link the Cryan/Crehan/Crean surnames to particular towns and the families of each town to each other. It will be possible to find connections between the Cryan/Crehan/Crean families in the 17th and 18th centuries which have eluded us up until now because of a paucity of archive resources.



Y-DNA testing explained: SNP markers,  STR markers and haplogroups

STRs are Short Tandem Repeat markers and SNPs are Single Nucleotide Polymorphisms, pronounced as “snips.” However, the benefit isn’t in the STR markers themselves, but in matching to other men. The markers are just the tool used – but the more information you have, the better the result. FamilyTreeDNA provides STR tests with their 37, 67 and 111 marker test panels, and comprehensive STR plus SNP testing with their Big Y-700 test. STR markers are used for genealogy matching, while SNP markers work with STR markers to refine genealogy further, plus they provide a detailed haplogroup. Think of a haplogroup as a genetic clan that tells you which genetic family group you belong to – both today and historically, before the advent of surnames.

STR markers are just markers and when used in testing YDNA they can be thousands of years old, useful for finding ancient haplotypes but not relevant for modern genealogy. Testing with the Big Y-700 finds SNPs, or haplogroups, of more recent times, within the era of surname use and valuable for building a Genetic Family Tree of the last 1000 years.

Initially, SNP results and haplogroups were so ancient that often they weren’t genealogically relevant, but that’s NOT the case anymore. Today, SNP results from the Big Y-700 test are sometimes MORE relevant and dependable than STR results. Each man receives a very refined personal haplogroup, known colloquially as their terminal SNP, often far more accurate than the estimated haplogroup provided with STR testing alone.

We encourage you to take part, and we promise you that you will be kept well informed of our progress through the FamilytreeDNA Cryan group (https://www.familytreedna.com/groups/cryan/activity-feed) and on our Facebook page.

See all Y-DNA products here : https://www.familytreedna.com/products/y-dna

Discovering history

By encouraging many people with Cryan/Crehan/Crean surnames we will be able to find out how we are connected to the famous O'Creans of the 17th century. The O'Crean family were an important, wealthy family, originally from Donegal but came to Sligo in the late 15th century and were merchants and landowners who held positions such as County Sheriff, Justice of the Peace, Dominican Priors, and Bishop of Elphin.

Join our Facebook Cryan/Crehan/Crean community DNA page at:
https://www.facebook.com/groups/676408537201195/

See also our archive page for help in general and historical knowledge and research: http://www.gaelart.net/familyhistory.html

 

Best wishes, Caoimhghin

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