Wow, this is complicated, thanks for the visuals, Cheri. Rosemarie [email protected] Researching Sao Jorge, Terceira, Graciosa, Faial and Pico, Azores, Isola delle Femmine, Sant' Elia, Sicily
On Fri, Feb 10, 2017 at 9:21 AM, Cheri Mello <[email protected]> wrote: > Sam said: > <<Speaking of new dna terms, what is the X match now shown on family > finder match pages?>> > > > > This one is reeeeally hard to explain in an email. It's tough enough in > person with a visual. > > > We have 23 pairs of chromosomes. The 23rd pair is the sex chromosomes. A > man is XY (the Y makes him a man and we have a Y DNA test for that) and a > woman is an XX. > > > The X match focuses on the X (or Xs if female) of this pair. > > > Let's start with a man, because he only has 1 X. > > His Y: from his dad. This is not an X. Eliminate his dad and the entire > pedigree beyond. > > His X: From his mom (#3 in chart below). She gave one of her 2 Xs to him. > Which one? Let's see, she got one X from her dad and 1 X from her mom. > > > Take that mom (#3 in chart below): > > X from her dad (#6): The only way she could get and X from her dad would > be if she inherited the X that was passed down by his mom (#13, as his Y > came from his dad). > > X from her mom (#7): She got either on of the Xs from her mom's parents > (#14 & 15). > > > Keep following that pattern of inheritance. > > > If you have your genealogy program create a fan chart and you color in the > people (Ahnentafel numbers are used here) you see this pattern. That way > you don't have to figure out the pattern of inheritance, it's already been > done for you: > > [image: NewChart4] > > > To get these graphics, just google: x match chart > > > For a female, it's twice the fun: > > [image: Image result for x match chart] > > > Here's what I would do: Instead of dealing with the scientific laws of > inheritance, I'd have my genealogy program print out a fan chart with names > (you may have to tape them together). I'd take a highlighter and mark the > names that correspond to my chart. > > > Because the way the X kinda recombines (or in the case of a man, it > doesn't), the general rule is: The X match MUST be 10 cMs or greater on the > X (23rd) chromosome AND you must be showing something in common on the > other chromosomes. > > > My dad is half Portuguese (paternal), and half British Isles stuff > (maternal). So his Y is Portuguese and his X is British. So I put his top 5 > X matches into the Chromosome Browser at FTDNA: > > [image: Inline image 1] > > Yes, I said 5 and you see 3 colors. The default display at FTDNA is 5 cMs. > So I changed it to 10 cMs. Same thing. Where are those other people? So I > changed it to 1 cM (WARNING!! DANGER!!! Will lead you to false > interpretations!!!) > > > [image: Inline image 2] > > A-ha! 5 colors for 5 people! BUT....when you point your mouse at it, a pop > up box appears that gives you more information. > > > ORANGE: 1st Cousin Nancy, half Welsh and half British stuff. You can see > where her Welsh took the bites out of her British. That's a 53 cM chunk > spanning the centromere and a 10 cM chunk at the end. > > GREEN: Robert. I haven't figured him out yet. It's a 15 cM chunk and he > matches on 2 other chromosomes with 9 and 14 cMs. One of those blocks has > the same start positition as 1st cousin Nancy. He's probably a 5th cousin, > so it would be best to wait this one out and find other 2nd-4th cousins to > fill this in. Jumping from a 1st to a 5th or so cousin might be rather hard. > > YELLOW: Karole. I haven't figured her out either. It's a 12 cM block. She > matches one other chromosome, spanning the centromere as well. It'll be a > distant cousin as well. > > > Now the 2 colors that didn't show up in the top chromosome: > > PURPLE: Maggie. She's probably on one of my dad's Irish lines that is > waaaaay back there. Her purple block is only 3.8 cMs and it straddles the > centromere. Straddling the centromere is a problem, particularly if it's a > small block. The centromere doesn't recombine. So it has some pretty old > stuff in there. That could be some tiny Irish DNA fragment. Maggie shares > only 1 other block with my dad. > > > BLUE: Julie. This is a problem. She's a Portuguese cousin 11 different > ways (so far). The closest is a 5th cousin. Julie's mom was Portuguese. We > don't know who Julie's dad was. My dad's X is British. This can't be > Portuguese. That block is only 3.7 cM. Could that be some common Irish > stock in both Julie and my dad? Yes. But trying to figure out which > ancestor for a 3 cM block wouldn't be the best use of time. I wouldn't > advise Julie to go chasing that block in trying to ascertain who her dad > was. She needs to work with much, much larger blocks of DNA to build that > part of her puzzle. > > > Now if you somewhat followed what I wrote, put it away and read it > tomorrow. And maybe the next day. Then read one of the following blogs. And > maybe another a few days later. If you read one thing on X match for a > week, it would start to make a bit more sense. > > > DNA Explained by Roberta Estes: https://goo.gl/lrmf3a > > The Legal Genealogist by Judy Russell: https://goo.gl/0NKUbZ > > The Genetic Genealogist by Blaine Bettinger: https://goo.gl/3scssd > > > Cheri Mello > Listowner, Azores-Gen > Researching: São Miguel island: Vila Franca, Ponta Garca, Ribeira Quente, > Ribeira das Tainhas, Achada > > -- > You received this message because you are subscribed to the Google Groups > "Azores Genealogy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > Visit this group at https://groups.google.com/group/azores. > -- You received this message because you are subscribed to the Google Groups "Azores Genealogy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/azores.
