FAQ
What is genetic genealogy?
Genealogy is the study of one's family tree and/or ancestry. Genetic genealogy is the use of DNA testing, alongside traditional genealogical methods (e.g. family trees, documentation and family history) to determine biological relationships between people. DNA testing is used by surname groups to discover the relationship between people sharing the same surname in order to complement one's paper trail. Sometimes when a paper trail is not available (e.g. a brick wall or before documented records), DNA testing can be used to infer biological relationships between individuals. For more information I would strongly recommend that you visit the website of ISOGG (International Society of Genetic Genealogy) : https://isogg.org
I have already traced and documented my family history. Why should I do a DNA test?
What different types of DNA tests exist?
The three main DNA test that are used in genealogy are :
An atDNA test looks at chromosomes 1-22, which are called autosomes. Each person has 44 autosomes, which is a total of 22 pairs of autosomes. Autosomes are inherited from both the mother and the father. Infact, for each pair of autosomes, one is inherited from the mother and one is inherited from the father. All people inherit 50% of their genes from their mother and 50% of their genes from their father. That does not mean, however, that you inherit 25% of your genes from each grandparent. What 50% you inherit from each parent is completely random. If you were to do an atDNA test, and then have your 4 grandparents test, you would discover that you are more closely related, genetically, to some of your grandparents than to others.
atDNA is the most popular form of testing today, because it will give you a good sense of your recent ancestry from both your paternal and maternal sides. However, from the 3rd cousin level, there is the distinct possibility that related people will not show up as matches due to something called recombination. Recombination is the process described above where, for each new generation, the mother and father's dna is randomly shuffled and passed on to the next generation. This makes atDNA better for looking at recent origins than ancestry that predates traditional paper records. For a surname project, atDNA does not go back far enough.
mtDNA Testing :
A mitochondrial DNA test looks at one's matrilineal ancestry by testing the DNA in the mitochondria, which is passed by a mother to her children unchanged. Both men and women can take a mtDNA test. However, only females pass on mtDNA to their children. This test can tell you if two people share maternal ancestry. However, given that mtDNA is slow mutating compared to both atDNA and yDNA, the shared ancestry can be quite ancient. As it is matrilineal it also does not get passed down with a surname in Western societies.
yDNA Testing :
A Y-chromosome DNA test looks at the 23rd pair of chromosomes, which is the sex chromosome. Females have two X-chromosomes, while men have an X-chromosome and a Y-chromosome. As such, only men can take a Y-chromosome DNA test. Unlike autosomes, the Y-chromosome is passed down from fathers to sons almost completely unchanged. This means that in comparison to an atDNA test, a yDNA test is suitable for looking at patrilineal descent. It is a great test for looking at patrilineal descent, because it is passed down almost entirely unchanged throughout 100s and even 1000s of years.
Since, most of us live in a society where surnames are passed down through the patrilineal line, there tends to be a strong connection between the Y-Chromosome and family surnames. In a surname study we can determine if people of the same surname are related to each other by doing a yDNA test. However, while a yDNA test can predict a surname, it can't tell us the exact nature of the relationship between individuals. For instance, a yDNA test cannot distinguish a father from a sibling, a grandfather or a 3rd cousin.
What are the different types of yDNA tests?
FTDNA offers two different types of yDNA tests : yDNA STR tests (Y37, Y67 and Y111) and yDNA SNP testing (Big Y700). The Big Y700 also includes results for 700 STRs, so it is actually a STR and SNP test.
I would suggest that you look at these three links for more information on the different yDNA tests :
https://learn.familytreedna.com/y-dna-testing/
https://learn.familytreedna.com/y-dna-snp-testing-haplogroups/
https://learn.familytreedna.com/y-dna-testing/big-y/big-y/
What is a haplogroup?
A haplogroup is a mutation (SNP) in the Y-chromosome that is shared by a group of people. These haplogroups are indicated by a letter from A to R. In Europe the majority of individuals belong to haplogroup R, which originated around 27000 BC. The haplogroups are further divided into subclades, which are subgroups of haplogroups. For instance, haplogroup R is divided into three subclades : R1a (predominantly Eastern European), R1b (predominantly Western European) and R2 (predominantly South Asian). Another important haplogroup in Europe is I. I is the only haplogroup that originated in Europe.
R1b is further divided into 2 major subclades in Western Europe : P312 and U106. P312 is the more common subclade, occurring in Romance, Celtic and Germanic regions, while U106 tends to be more restricted to Germanic regions.
To which subclades do Worrall people belong?
At this point all the participants in the project are R1b +, P312 +, DF19+. P312 is the the most common subclade of R1b. P312 dates back to the bronze age. Soon after P312 split into 6 subclades with 3 being very common : L21 (North Atlantic, especially common in Celtic groups), DF27 (Iberian) and U152 (Alpine, Austria/Northern Italy/Switzerland) and 3 being comparatively rare : DF19 (North sea, Anglo-Saxon/Norman/Scandinavian), DF99 (Germanic) and L238 (Norse).
Being DF19+ means that the current Worrall testers descend from a Germanic group. Further testing can help us refine which group that might be. DF19 is closely associated with Norman ancestry in England, Ireland, Wales and Scotland, so it is tempting to assume that this means the Worrall family is Norman in origin, which would fit with family histories, but further testing is needed to prove or disprove that.
There are also some Worralls who had tested positive for I-M253, which is also very indicative of Germanic ancestry.
This means, however, that there are at least two separate families that carry the surname Worrall. My working theory is that the DF19+ group is the Worrall family that originates in the Wirral Peninsula, while the I-M253+ group is the Worrall family that is named after Worrall village in the West Riding of Yorkshire. Having more people test will provide clarity on this matter.
What is a terminal SNP?
A terminal SNP is the most recent mutation in the yDNA that is shared with another person. For example, my father and I share the terminal SNP R-BY138926. My father’s fifth cousin has R-BY79362 as his terminal SNP. My father and I are also positive for R-79362, but my father’s fifth cousin is negative for R-BY138926. This is valuable, because it tells us that R-BY138926 originated after our common ancestor, William Worrall (1747-1827).
What is a private SNP?
Private SNPs are those that are unnamed, because only one person has been found positive for the SNP. For example, I have a SNP that is unique to me that my dad does not share. These are noted by a number, which is the position where the SNP is found on the Y-Chromosome. In this case the SNP is a private variant called 15597397. When another person tests positive for a private SNP, it is named and becomes a new branch of the yDNA tree.
What is an equivalent SNP?
These are mutations that are located in the same haplogroup or subclade. These SNPs cannot be put in chronological order until someone tests negative for one of the equivalent SNPs. When someone tests negative, the group of equivalent of SNP is rearranged in chronological order.
For example, let's suppose a father and a son both did the BigY test and they were found to be share SNPs BY100001, BY100002, BY100003,BY100004, BY100005 and BY100006. Later, a 6th cousin does the BigY. He is found to be positive for BY100001, BY100004 and BY100006, but negative for BY100002, BY100003 and BY100005. The group of 6 equivalent SNPs would be broken into two new branches of three SNPs (BY100001, BY100004, BY100006 and BY100002, BY100003, BY100005). The SNPs for which the 6th cousin tested negative can be said to be downstream of the SNPs for which he tested positive. To say a SNP is 'downstream' of another SNP means that it is more recent. Whereas if we say a SNP is 'upstream' of another SNP, we are saying that it is older.
In some cases this is not possible to separate equivalent SNPs. For instance, suppose that a SNP occurs in a man and then another SNP occurs in his great grandson. If the only descendents come from the great grandson, we cannot say which SNP comes first.
In most cases groups of equivalent SNPs can be broken up through more people testing, which is very important for dating SNPs and distinguishing branches of surname families.
What is the difference between a STR and a SNP?
A STR is a place in the DNA where a letter code is repeated. A SNP is a change in the DNA. STRs change more rapidly than SNPs. We can predict one's haplogroup based on a STR signature, but we can only confirm a haplogroup through SNP testing, as ultimately haplogroup placement is based on having a specific SNP in one's Y-Chromosome.
Genealogy is the study of one's family tree and/or ancestry. Genetic genealogy is the use of DNA testing, alongside traditional genealogical methods (e.g. family trees, documentation and family history) to determine biological relationships between people. DNA testing is used by surname groups to discover the relationship between people sharing the same surname in order to complement one's paper trail. Sometimes when a paper trail is not available (e.g. a brick wall or before documented records), DNA testing can be used to infer biological relationships between individuals. For more information I would strongly recommend that you visit the website of ISOGG (International Society of Genetic Genealogy) : https://isogg.org
I have already traced and documented my family history. Why should I do a DNA test?
- DNA testing can confirm your family history;
- DNA testing can help you discover new relatives, such as those who were adopted or those who do not know their family history;
- DNA testing can help you confirm your deep origins (e.g. if your family is Norman, Anglo-Saxon, Norse, Celtic etc...);
- DNA testing can give you a good idea of your ancestry before surnames were adopted and family histories were written;
- DNA testing can give you a good idea of when branches of a surname family split as well as the rough age of these different branches.
What different types of DNA tests exist?
The three main DNA test that are used in genealogy are :
- Autosomal DNA test (atDNA)
- Mitochondrial DNA test (mtDNA)
- Y-chromosome DNA test (yDNA)
An atDNA test looks at chromosomes 1-22, which are called autosomes. Each person has 44 autosomes, which is a total of 22 pairs of autosomes. Autosomes are inherited from both the mother and the father. Infact, for each pair of autosomes, one is inherited from the mother and one is inherited from the father. All people inherit 50% of their genes from their mother and 50% of their genes from their father. That does not mean, however, that you inherit 25% of your genes from each grandparent. What 50% you inherit from each parent is completely random. If you were to do an atDNA test, and then have your 4 grandparents test, you would discover that you are more closely related, genetically, to some of your grandparents than to others.
atDNA is the most popular form of testing today, because it will give you a good sense of your recent ancestry from both your paternal and maternal sides. However, from the 3rd cousin level, there is the distinct possibility that related people will not show up as matches due to something called recombination. Recombination is the process described above where, for each new generation, the mother and father's dna is randomly shuffled and passed on to the next generation. This makes atDNA better for looking at recent origins than ancestry that predates traditional paper records. For a surname project, atDNA does not go back far enough.
mtDNA Testing :
A mitochondrial DNA test looks at one's matrilineal ancestry by testing the DNA in the mitochondria, which is passed by a mother to her children unchanged. Both men and women can take a mtDNA test. However, only females pass on mtDNA to their children. This test can tell you if two people share maternal ancestry. However, given that mtDNA is slow mutating compared to both atDNA and yDNA, the shared ancestry can be quite ancient. As it is matrilineal it also does not get passed down with a surname in Western societies.
yDNA Testing :
A Y-chromosome DNA test looks at the 23rd pair of chromosomes, which is the sex chromosome. Females have two X-chromosomes, while men have an X-chromosome and a Y-chromosome. As such, only men can take a Y-chromosome DNA test. Unlike autosomes, the Y-chromosome is passed down from fathers to sons almost completely unchanged. This means that in comparison to an atDNA test, a yDNA test is suitable for looking at patrilineal descent. It is a great test for looking at patrilineal descent, because it is passed down almost entirely unchanged throughout 100s and even 1000s of years.
Since, most of us live in a society where surnames are passed down through the patrilineal line, there tends to be a strong connection between the Y-Chromosome and family surnames. In a surname study we can determine if people of the same surname are related to each other by doing a yDNA test. However, while a yDNA test can predict a surname, it can't tell us the exact nature of the relationship between individuals. For instance, a yDNA test cannot distinguish a father from a sibling, a grandfather or a 3rd cousin.
What are the different types of yDNA tests?
FTDNA offers two different types of yDNA tests : yDNA STR tests (Y37, Y67 and Y111) and yDNA SNP testing (Big Y700). The Big Y700 also includes results for 700 STRs, so it is actually a STR and SNP test.
I would suggest that you look at these three links for more information on the different yDNA tests :
https://learn.familytreedna.com/y-dna-testing/
https://learn.familytreedna.com/y-dna-snp-testing-haplogroups/
https://learn.familytreedna.com/y-dna-testing/big-y/big-y/
What is a haplogroup?
A haplogroup is a mutation (SNP) in the Y-chromosome that is shared by a group of people. These haplogroups are indicated by a letter from A to R. In Europe the majority of individuals belong to haplogroup R, which originated around 27000 BC. The haplogroups are further divided into subclades, which are subgroups of haplogroups. For instance, haplogroup R is divided into three subclades : R1a (predominantly Eastern European), R1b (predominantly Western European) and R2 (predominantly South Asian). Another important haplogroup in Europe is I. I is the only haplogroup that originated in Europe.
R1b is further divided into 2 major subclades in Western Europe : P312 and U106. P312 is the more common subclade, occurring in Romance, Celtic and Germanic regions, while U106 tends to be more restricted to Germanic regions.
To which subclades do Worrall people belong?
At this point all the participants in the project are R1b +, P312 +, DF19+. P312 is the the most common subclade of R1b. P312 dates back to the bronze age. Soon after P312 split into 6 subclades with 3 being very common : L21 (North Atlantic, especially common in Celtic groups), DF27 (Iberian) and U152 (Alpine, Austria/Northern Italy/Switzerland) and 3 being comparatively rare : DF19 (North sea, Anglo-Saxon/Norman/Scandinavian), DF99 (Germanic) and L238 (Norse).
Being DF19+ means that the current Worrall testers descend from a Germanic group. Further testing can help us refine which group that might be. DF19 is closely associated with Norman ancestry in England, Ireland, Wales and Scotland, so it is tempting to assume that this means the Worrall family is Norman in origin, which would fit with family histories, but further testing is needed to prove or disprove that.
There are also some Worralls who had tested positive for I-M253, which is also very indicative of Germanic ancestry.
This means, however, that there are at least two separate families that carry the surname Worrall. My working theory is that the DF19+ group is the Worrall family that originates in the Wirral Peninsula, while the I-M253+ group is the Worrall family that is named after Worrall village in the West Riding of Yorkshire. Having more people test will provide clarity on this matter.
What is a terminal SNP?
A terminal SNP is the most recent mutation in the yDNA that is shared with another person. For example, my father and I share the terminal SNP R-BY138926. My father’s fifth cousin has R-BY79362 as his terminal SNP. My father and I are also positive for R-79362, but my father’s fifth cousin is negative for R-BY138926. This is valuable, because it tells us that R-BY138926 originated after our common ancestor, William Worrall (1747-1827).
What is a private SNP?
Private SNPs are those that are unnamed, because only one person has been found positive for the SNP. For example, I have a SNP that is unique to me that my dad does not share. These are noted by a number, which is the position where the SNP is found on the Y-Chromosome. In this case the SNP is a private variant called 15597397. When another person tests positive for a private SNP, it is named and becomes a new branch of the yDNA tree.
What is an equivalent SNP?
These are mutations that are located in the same haplogroup or subclade. These SNPs cannot be put in chronological order until someone tests negative for one of the equivalent SNPs. When someone tests negative, the group of equivalent of SNP is rearranged in chronological order.
For example, let's suppose a father and a son both did the BigY test and they were found to be share SNPs BY100001, BY100002, BY100003,BY100004, BY100005 and BY100006. Later, a 6th cousin does the BigY. He is found to be positive for BY100001, BY100004 and BY100006, but negative for BY100002, BY100003 and BY100005. The group of 6 equivalent SNPs would be broken into two new branches of three SNPs (BY100001, BY100004, BY100006 and BY100002, BY100003, BY100005). The SNPs for which the 6th cousin tested negative can be said to be downstream of the SNPs for which he tested positive. To say a SNP is 'downstream' of another SNP means that it is more recent. Whereas if we say a SNP is 'upstream' of another SNP, we are saying that it is older.
In some cases this is not possible to separate equivalent SNPs. For instance, suppose that a SNP occurs in a man and then another SNP occurs in his great grandson. If the only descendents come from the great grandson, we cannot say which SNP comes first.
In most cases groups of equivalent SNPs can be broken up through more people testing, which is very important for dating SNPs and distinguishing branches of surname families.
What is the difference between a STR and a SNP?
A STR is a place in the DNA where a letter code is repeated. A SNP is a change in the DNA. STRs change more rapidly than SNPs. We can predict one's haplogroup based on a STR signature, but we can only confirm a haplogroup through SNP testing, as ultimately haplogroup placement is based on having a specific SNP in one's Y-Chromosome.