RootsChat.Com

Quote from: Lubana on Sunday 26 May 19 15:02 BST (UK)

The gray
I have no idea what experts you have spoken to--but difficult doesn't mean impossible.  A man's autosomal DNA is not a clone of that of his father.  In autosomal DNA, everyone has two alleles at every marker or locus, one donated by the father and one by the mother.  Obviously a father and his son do not have the same mothers.  Their DNA will look different, even though the son received an allele from the father at every marker.  What will look the same is their y-DNA, which is a different story.  Let's say Dad has these alleles, shown as numbers at a marker----12/23.  His female partner has 8/10.  Son will receive a number from each parent out of a possibility of four combinations.  Let's say he receives  10/23.  That illustrates why his DNA is not the same as that of his father.  Now Son can pass down nothing but 10/23 at that marker to his own children.  But Dad can only pass down 12/23 no matter what.  It doesn't take a rocket scientist to figure out that if Offspring has a 10 at the same marker, combined with another number from his or her Mom, it will not have come from Dad--but Son.

"It would certainly make things easier if it was possible to test the husband and his father, but both of these people had died before DNA testing became generally available as was the mother but perhaps you missed that small point."

You never mentioned that all were deceased, so what was there to miss?  And how is all that the fault of some testing company?  Wasn't that your original point--their so-called lack of accuracy?  If the possible fathers are deceased, then there can't be a paternity test.  There is the possibility of autosomal testing and receiving some DNA relatives, the distance of relativity being calculated.  Let's say the deceased possible father, old Dad, had some other children.  What relationship of Offspring to them?  Or old Dad had some siblings with their own offspring--same question.  In that case, none of the potential fathers need to be alive.  All that's required is luck.

[snip of irrelevant stuff about ethnicity from Guy Etchells]

Quote from: Lubana on Sunday 26 May 19 15:02 BST (UK)

People who have been able to compare their DNA to other close family members on a site like Ancestry know just how accurate that is.  Parents share about 50% of their DNA with their children and, likewise, full siblings share roughly 50% as well.  That comes out to about 3, 500 centimorgans, give or take.  Almost needless to say, the more distant the relationship, the fewer cMs.  This is a good checking source, if in doubt.

https://dnapainter.com/tools/sharedcmv4/1089

Worrying about whether an identical twin brother of someone might have been your father is rather pointless, IMO, as it is so unlikely to have been the case,  It is only identical twins that have the same DNA.  Fraternal twins are like any other full siblings when it comes to DNA.  50% of it will be different.

"It may be pointless to you but I can assure you that when a mother just before she dies of cancer tells one of her daughter’s her father is really her grandfather that daughter does not think it pointless. "

Hold on--what does this have to do with what I said about identical twins?  In fact, I fail to see your point at all. 


"In the above case the mother and her three elder daughters were living in the grandfather’s home while her husband was serving a prison sentence. There is very little chance the mother did not tell the truth, unless the daughter was born very premature or late but there was no hint of that.
Every DNA expert I have spoken to agrees it would be very difficult to discover the birth father via DNA."

I have no idea what experts you have spoken to--but difficult doesn't mean impossible.  A man's autosomal DNA is not a clone of that of his father.  In autosomal DNA, everyone has two alleles at every marker or locus, one donated by the father and one by the mother.  Obviously a father and his son do not have the same mothers.  Their DNA will look different, even though the son received an allele from the father at every marker.  What will look the same is their y-DNA, which is a different story.  Let's say Dad has these alleles, shown as numbers at a marker----12/23.  His female partner has 8/10.  Son will receive a number from each parent out of a possibility of four combinations.  Let's say he receives  10/23.  That illustrates why his DNA is not the same as that of his father.  Now Son can pass down nothing but 10/23 at that marker to his own children.  But Dad can only pass down 12/23 no matter what.  It doesn't take a rocket scientist to figure out that if Offspring has a 10 at the same marker, combined with another number from his or her Mom, it will not have come from Dad--but Son.

Quote from: Lubana on Sunday 26 May 19 15:02 BST (UK)

The gray area involves ethnicity.  While one company will identify you as 30% British, say, another will assign you perhaps 38%.  All you can deduce from that is that you have a significant amount of British ancestry.  Another company--not Ancestry--at one time assigned me some small bits of interesting ethnicity--and ended up taking that away for a reason I have yet to understand.  But, if one can acknowledge a lack of complete accuracy in that aspect of ones DNA results, one can live with it.  It is not to be confused with the accuracy of relationships between people, that's all.  The reliable testing companies look at hundreds of thousands of markers, not just a few.  You can bank on the results.

I think my views on ethnicity results are well known.

With regards to the accuracy of DNA

The population of London in 2018 was 8,787,892 the largest worldwide DNA database is estimated at 12,777,778 in other words half as much again as 1 city or if you compare this to the world population of 7.6 billion (in 2018) in other words a small proportion.

A lot of claims are made about DNA but at present it is still very much a tool in the genealogists toolbox that relies heavily on other tools to produce results.

Your views on DNA may be well known [but not to me] so forgive me if I question *their* acciracy.  The population of London now or at any other time has nothing to do with the accuracy of DNA testing.

People who have been able to compare their DNA to other close family members on a site like Ancestry know just how accurate that is.  Parents share about 50% of their DNA with their children and, likewise, full siblings share roughly 50% as well.  That comes out to about 3, 500 centimorgans, give or take.  Almost needless to say, the more distant the relationship, the fewer cMs.  This is a good checking source, if in doubt.

https://dnapainter.com/tools/sharedcmv4/1089

Worrying about whether an identical twin brother of someone might have been your father is rather pointless, IMO, as it is so unlikely to have been the case,  It is only identical twins that have the same DNA.  Fraternal twins are like any other full siblings when it comes to DNA.  50% of it will be different. 

The gray area involves ethnicity.  While one company will identify you as 30% British, say, another will assign you perhaps 38%.  All you can deduce from that is that you have a significant amount of British ancestry.  Another company--not Ancestry--at one time assigned me some small bits of interesting ethnicity--and ended up taking that away for a reason I have yet to understand.  But, if one can acknowledge a lack of complete accuracy in that aspect of ones DNA results, one can live with it.  It is not to be confused with the accuracy of relationships between people, that's all.  The reliable testing companies look at hundreds of thousands of markers, not just a few.  You can bank on the results.

I've never seen the name "Janto" among the Italians--especially since the Italians don't use the letter "j" in their writing.

Just to recap:  My cousin and I have several DNA matches in common on Ancestry.  They are among my closest matches there.  One of these matches [who shares the most DNA with me after my cousin] was linked to my cousin's maternal grandmother, Harriet Riley, or rather one of Harriet's sisters [not Louisa Richardson].  Therefore, I had to conclude that I am connected to that maternal side.

Because of the amount of centimorgans we have in common, my biological father has to be a very close relative of hers.  She had two uncles on her mother's side, one named Brooker and the other named Berry.  The trouble is that neither of them can be placed in my town of Wesel in Germany at the time I should have been conceived.  Albert Brooker was a seaman and, according to my cousin, Lawrence Berry was stationed in India and demobbed in Italy.  This last is consistent with what I know about the British army in India, which was a volunteer army until 1939.  Later, out of necessity, the India troops were sent west to the Mediterranean area and perhaps also to desert warfare and many of them were demobbed in Italy at the end. 

On her father's side there are more possible men but I have not been able to connect myself to that side.  By sheer coincidence, my cousin has another DNA relative who lives not more than 40 miles from me--but that relative knows she is descended from a common paternal ancestor with my cousin.  As far as I know, that relative is not among our common matches.  My Ancestry.com DNA relatives map shows me as being alone in my own state--where I have only lived for the past 14 years.  Therefore, my only chance on my cousin's maternal side [insofar as I know] is if her great-aunt, Louisa Riley Richardson, had a son.  Her husband, if you recall, was John Robert Richardson of Hull.  He was born in 1883--but I did find another John Robert Richardson born in Hull in 1916.  Yet I have not been able to find out the names of his parents in order to securely place him within the family. 

The reason I believe that my connection to my cousin is not some sort of mistake within the DNA testing lab is that we do have those common DNA relatives and, also, my daughters got her as a relative before I ever tested with Ancestry.  She was a mystery to them and so I was asked to test in order to try to shed some light.  It turned out I am a closer match with my cousin than my daughters are, which makes sense.  Somewhere out there is the reason for this but that is elusive thus far.  My youngest sister offered to test with Ancestry to determine if we are really full sisters and, although we do share more DNA than most half-siblings, the tool mentioned in this thread indicated the great likelihood is that we are no more than that--half-siblings.