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Costa Rican Maternal Cousin shares a few paternal Puerto Rican matches

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  • Costa Rican Maternal Cousin shares a few paternal Puerto Rican matches


    I am new to FTDNA and to the forums.

    I recently uploaded the RAW DNA of my mom, maternal grandmother, maternal (male) half-cousin, paternal uncle and mine. Also, I linked their DNA to my family tree.

    A little backstory:

    My mom, maternal grandmother and maternal half-cousin are from Costa Rica. Even their DNA has a high percentage of Native American (40s% for my mom and grandmother and about 34% for my half-cousin). All of them had Costa Rican parents/grandparents, etc. I was born in Puerto Rico and my dad was from Arecibo, Puerto Rico.

    When I selected my half-cousin and clicked the " = in common with" I noticed that we share 6 people in the "paternal tab" and 104 in the "maternal tab". I was surprised to see that we have 6 people in common in the paternal side.

    I share 101 cM / 20 longest block / 2nd cousin - 4th cousin with one of the paternal matches with my Costa Rican maternal male half-cousin. My half-cousin only shares 45 cM / 9 longest block / 5th cousin - remote cousin with this person. I contacted this person and he said that he doesn't have "any Costa Rican blood. Both parents were born in Puerto Rico just like his grandparents. Also, his dad's family came from the Canary Island and on his family from his mother's side came from Barcelona".

    When I selected this person that I have in common with my cousin and clicked "=in common with" I share with this person my "paternal uncle and a paternal first cousin" and also my Costa Rican maternal half cousin.

    Since I am not an expert and I know many of you are way more knowledgeable than me, maybe someone can explain this phenomenon. Why do I have a few shared paternal side with my Costa Rican cousin when his parents/grandparents, great grandparents are from Costa Rica. I asked this "person" if he is on Gedmatch or Ancestry and he said he is not.

    This weekend my Costa Rican half-cousin's dad is doing his DNA through Ancestry. Hopefully, that will answer many questions.

    Last edited by XuxaDNA; 12 September 2019, 12:37 PM.

  • #2
    What is the indigenous percentage (estimate) for "this person" ? In our experience Ticos with a high indigenous percentage match random people all over the Americas. We've chalked up Chile, Bolivia, Ecuador, Peru, Panama, Columbia, Nicaragua, Mexico, Guatemala. Usually people with estimates of >30% indigenous. Haven't noticed Puerto Rico but not surprised. The algorithms were designed for Europeans. Pay attention only to the size of the largest shared segments. Not total amount shared. Not predicted relationship. Not the "paternal/maternal" tabs. Only the segment size, and even that can be misleading. One member of our family shares a segment of about 12cM with a 12k old skeleton.


    • #3
      What is the indigenous percentage (estimate) for "this person" ?
      Very interesting.. Well, "this person" new world percentage is 14%.
      My Costa Rican mom 44%
      My Costa Rican grandmother: 46%
      My Costa Rican half-cousin: 34%
      My paternal Puerto Rican uncle (both Puerto Rican parents): 17%
      Me: 33%