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1262Re: [MexicoDNAProject] New User Confusion

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  • Randal Soza
    Jun 9, 2014
      Hi Michael! DNA can be a very daunting subject for anyone "new" to the science. I suggest that you just read, and read, and read as much information as you can on the subject, and you will find that over time it will get easier and easier to understand.  I will attempt to answer your questions for you, although I'm not the best at explaining things as some others are.

      1. - Y DNA Haplotree.......you can think of it like a backwards family tree. What DNA science has tried to do, both Y and mT, is to place people into categories (branches) based on the groups of mutations found in the DNA structure. Supposedly, we can trace our evolution back to chromosomal Adam (Y DNA) and chromosomal Eve (mT DNA). I say supposedly because it's all theory still, and has never been proven as fact. Anyways, let's say "Adam" had 3 sons. Each son has a slightly different sequence of proteins on his DNA chain. These differences are called "mutations". Now these sons have have offspring, and their sons have offspring and so on and so on. Now in order to differentiate between who is who, I must categorize them. So I will name this group of people haplogroup A. His sons will be A1, A2, and A3, meaning they came from Adam and son 1, 2, and 3.....or family branches. Now, son number 1 had a couple more sons and each one had a different mutation, so to differentiate between these two, I can say son 1 will be A1a and son 2 will be A1b, and so on and so on. Now lately, some of these category names were getting really long, like R1b3c1a1a1a2b1c1a1a1a1c, so scientists decided to use shorthand names for each group like "M201", or "L91", or "P93" which I believe makes it more confusing for people that do not know the science behind it all. Now, FTDNA does a basic haplogroup assignment, giving you your main haplogroup identity like R1b, and then you can order more tests, and narrow your grouping down even further. This is a very basic explanation, but I hope it helps. FTDNA does have a "FAQ" page that you can go to for more help.

      2. - some people have many, many brother lines, and some have none at all. These people who don't have any matches in their Y DNA are considered genetic isolates. I know this well, because my family also has no close genetic matches either. Over time, as more and more people get tested, we make get more matches. Or it could be that your DNA belongs to a group whose branches have been repeatedly wiped out over time (like the Jews). Only time will tell, but I must ask you, what is your Y DNA haplogroup?

      3. - the MyOrigins is using the past 12 generations on average, give or take a few generations, but FTDNA also uses something called "AIMS" in helping to identify ancient autosomal markers. AIMS stands for Ancestral Informative Markers. These can help place DNA into geographic regions on an even "older" level, although there is much speculation within the scientific community as to how well these AIMs work.

      4. - I've never ever seen it where someone who is a closer relative has less CM than a more distant one. According to the example you gave, the 48.10cm falls into about a 3rd cousin, and the 92.53 falls into about a 4th cousin, so the third cousin should have more cm than the 4th. BUT, those classifications are only "guesses" by the FTDNA computer. That's why they give a range, and not an exact match for relation. So it could very well be that the 42cm is a 4th cousin, which is within the relationship range given, and the 92cm is a 3rd cousin or even 2nd cousin........according to the laws of DNA recombination, the CM gets roughly halved with each generation, so obviously the person with 92 is one generation ahead of the other person.

      These are just basic answers, but I hope it helps some.

      Randal Soza

      Jewish Mexico Arizona Southwest US DNA Project Admin

      On Jun 9, 2014, at 4:24 AM, "mickeygreencherry@... [MexicoDNAProject]" <MexicoDNAProject@yahoogroups.com> wrote:


      Thank you for reading this - I enjoy the posts very much. Alas, it is abundantly clear I do not know what I am doing.  I find FTDNA pages rather cryptic and am hoping someone will be kind and willing to help me with my questions:

      1).  The Y-DNA Haplotree - any information on how to read it a meaningful way. It seems that page could benefit from the help button, but there is none.  Perhaps there is a help page, but I could not find it.

      2).  I was very hopeful that I would get some clues on the cryptic lineage of my father.  The fact that Y-DNA results came up with only one match and it is someone not even in the Mexico DNA project is a bit discouraging.  In fact, even in Y-search the matches are seemingly not helpful.

      3). The My Origins heat map is fun; but I am not sure what time period it is representing.

      4). How does one have matches with greater cM that are lower in the relationship range (for example: 48.10 cM = 2nd cousin - 4th cousin v.  92.53 cM = 3rd cousin - 5th cousin)?

      Such is my confusion.
      Thank you for any considerations.

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