? asked in Science & MathematicsBiology · 2 months ago

How does ethnic ancestry work with Chromosomes?

So let me preface with what I do know about genetics and Chromosomes so that If I am incorrect, I can be corrected.

Since I am a "normal" human, I have 23 Chromosomes total including the sex Chromosomes. Each Chromosome contains a myriad of DNA from both your mother and your father. Exactly 50% of the DNA comes from the mother, and 50% comes from the father, and it is essentially a random mix of both, but some genes are more dominant.

I am a male, ergo, I have one X Chromosome that comes from my mother (it is one of her two X Chromosomes, and one Y Chromosome (which is an exact "copy" of my father's Y Chromosome that is an exact "copy" of his father's Y Chromosome, etc.). If I was a woman, I would receive the only X Chromosome from my father, and one of the X Chromosomes from my mother.

I was doing some brief research on Ancestry tests like "23 and Me" and whatnot, and they were talking about Y-DNA ancestry (father) and Mitochondrial ancestry (mother).

I was confused when it said, "Y-DNA". Are the genetic Haplogroups and ethnicity marking genes stored in the sex Chromosomes or mixed throughout the other 22 Chromosomes? Would an ancestry test like 23 and Me show my dad's mother's ethnicity, or even his grandmother's and so on, or just his Father's (because of the Y Chromosome)? Would it show me my mother's father's ethnicity or even his father's? Or would I simply see only my mother's mother's?


Also, please forgive my ignorance on the subject of genetics. My training is in Geology.

1 Answer

  • Zirp
    Lv 7
    2 months ago

    ethnicity isn't about DNA. You have 23 PAIRS of chromosomes, each pair consisting of one from your father and one from your mother. You also have mitochondrial DNA from your mother. Combined, that's 47 independent bundles of DNA. A DNA-"ancestry"-test  compares your bundles to those of the people that that specific company has tested before. In most cases they will find some distant cousins of yours as you share one or a few bundles with them. You share exactly 23 chromosomes with your parent/child, and about 23 with a full sibling. For more distant bloodrelatives it's a lottery. There is no exact 11.5 chromosomes

    > Would an ancestry-test like 23 and Me show my dad's mother's ethnicity, or even his grandmother's and so on?

    No, not at all


    • ?2 months agoReport

      If "ethnicity has nothing to do with DNA", then what are Haplogroups then (like Haplogroup R1b). I know for a fact that those are a cluster of Gene's at are shared among a certain ethnic group.

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