Chromosomes

[phil57]

Not a daft question at all Louisa, but it is quite a complex one. There are two sex chromosomes, referred to as X and Y. All males have one X chromosome, inherited from their mother, and one Y chromosome inherited from their father. Females have two X chromosomes, one inherited from their mother and one from their father.

So a child can only inherit an X chromosome from it's mother, because females don't have a Y chromosome. But it can inherit either an X or a Y chromosome from it's father, because a male has one of each type. Which chromosome it inherits from it's father determines it sex.

Since the Y chromosome is only passed down the male line it can be used to investigate the direct paternal line. That involves taking a separate and more expensive test than the more common autosomal tests offered by Ancestry and similar companies.

A different type of DNA called mitochondrial or mtDNA can be used in a similar way to investigate the female line. It is separate from the nuclear DNA tested for autosomal matching, and is passed down by a mother to all her children, both male and female, but only the female children can pass it on to their children. So it can be used to investigate the direct maternal line, but the line will be broken if a mother only has male children. mtDNA tests are also more expensive than autosomal tests.

I wouldn't recommend taking either a Y DNA or mtDNA test unless you have taken advice and understand what you might get from them and whether they will be of any help to you.

That's the brief answer I'm afraid. I don't have much more than a basic understanding of either Y DNA or mtDNA myself!

I hope that makes sense. I'm typing this on my phone since my PC failed yesterday, and it's not so easy to keep track of what I'm typing.

[louisa maud]

Many thanks Phil 57, it is a bit complicated for me but it does make sense, contradicted myself there I suppose
I don't think I will do any DNA tests,  will  stick with what I have
Hope your PC recovers
Many thanks for your explanation,  it just might help others as well

LM

[Biggles50]

One of my Great Grandmother’s on my Paternal line has no Father listed on her birth certificate.

The man her Mother went on to marry many years later was only 10 years old when my Great Grandmother was born so he can be discounted.

Searching the local Archives there are zero Court records.

Searching British Newspapers there is no trace of her Mother initiating any search or proceedings against the Father.

So I have zero paper trail for her, just her individual BMD, Census etc

Then a new reasonably high cM match gives a hypothesis that the match’s Great Great Grandfather may be the missing Father.

It took ten years before the DNA match showed up.

So I would not discount having a DNA test done, if there are no paper trails it is all there is, unless somewhere out there there are records still waiting to be transcribed and catalogued, either way it can be a waiting game.

Good Luck in your quest

[louisa maud]

The reason I wanted to find out if there  was  a  maternal and paternal  separately  was I am showing  a small % East Europe, apart from my gt grandfather being Swedish, and it didn't show up as so  I wondered where it came from, I am 94% English,  the 6% is small smattering  of Scottish, Irish and Welsh, my fathers parents were  barges and although always shown as being born in London I  haven't been able to get back further that 1800, 

Thank you for your suggestions but will stick with what I have so far but it does intrigue me as to how these Tv progress come up with named fathers  who prior to  DNA   were unknown and unamed

LM

[strictlysnoopy]

       

         Is it correct to add two of the highest centremorgans together and then claim to be a closer cousin?
   Thanks

[phil57]

I would say no, but if your match wishes to assert that, then ask him to show how he believes you are related, and provide his evidence of a documented paper trail to support his claim.

I manage my brother's test. Obviously, as we are brothers, any matches that we share or each have are related to both of us in the same way. I could provide plenty of instances where I have a match to a cousin but my brother doesn't, and vice versa. We also have many matches where the amount of DNA that the match shares with each of us is quite different.

One example, a second cousin who matches me at 226 cM across 7 segments; largest segment 118 cM. The same cousin matches my brother at 131 cM across 8 segments; largest segment 40 cM.

As you have previously stated, you have a documented paper trail for your match as 3C1R. Your match is pretty much on the mean value for a relationship at that level. But anywhere between no DNA match at all to 192 cM could also be consistent with that relationship according to the cases used by DNA Painter.

DNA inheritance is random. You inherit about 50% of your DNA from each of your parents, as would a brother or sister of yours. But it doesn't mean that they would inherit the same DNA from each parent. You could theoretically inherit only 1% of you paternal GF's DNA and 49% of your paternal GM's. Similarly with your maternal grandparents. Your brother might inherit 49% of your paternal GF's DNA and only 1% of your paternal GM's. An extreme example, in practice the variances will not be as great, but with each generation that you go back the imbalance will likely increase as more GG parents, GG grandparents, etc. DNA is added to the mix and similarly randomly inherited from their parents.

[strictlysnoopy]

   

    Thank you Phil,   Really hope you plan to write a book.

         Knew in my heart of hearts that it was not right, but he insisted.   It’s a long time since O level biology  .    When somebody is so insistent it makes you doubt ourself.

       Thanks for all your replies I really appreciated them.   Keep safe, hoping your computer is good to go now 😁

[Zaphod99]

Try YouTube for gedmatch

Mrs Zaph



quote author=strictlysnoopy link=topic=870283.msg7413541#msg7413541 date=1676499539]
     

       Ancestry results as follows

           23cMs   3 segments

           Unweighte shared DNA.  50cMs

           Longest segment.  21cMs

          It was Gedmatch that gave a two chromosome match between us. Sorry that is all I know as I find Gedmatch very difficult to use.   

      Thanks

         
[/quote]

[strictlysnoopy]

        Great detective work.   On Ancestry are you parent 1or 2?     
     

    Gedmatch has so much info, but  agree so difficult to navigate, esp for newbies 😁

         Is your Gedmatch name the same as above?   Will try my best to find you,  could be messaging you before long 😂