Race, Ancestry, and Relatedness

1 - 10 of 84 Answers

November 11, 2019: What’s the difference between shared centimorgans and shared segments?
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October 24, 2019: It seems like the metrics used to show genetic relatedness are contradictory. We read that siblings are approximately 50% alike; we also read that the average difference between any two humans is anywhere from .1% to .6% (implying 99%+ alike); and we also read that humans and chimpanzees share approximately 99% of their DNA. Can you explain what these various ratios are based upon? 
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October 15, 2019: Can you marry a second cousin? What about a first cousin or half sibling?
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May 6, 2019: Two of the characters on Game of Thrones are full siblings. They committed incest and have 3 children together. With just that information what percentage of DNA would the children share with each other? And what percentage would they share if their parents were only half siblings?
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April 2, 2019: I learned through 23andMe that I have a half-sister. However, my father was an identical twin, so this woman also matches with my cousin as a half-sister. Both twins are deceased. Is it possible to solve the mystery of which twin is actually her father?
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February 19, 2019: I have two half-siblings and share DNA with one at 28.7% and the other at 24.6%, which I assume is normal.  However, according to the 23andMe, the brother sharing the most DNA shares only 47 segments versus 55 segments with the other brother.  Is this also considered normal?
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November 29, 2018: How exactly do paternity tests work?
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January 8, 2018: What is the best genetic test for telling whether my brother is a full or half-brother?
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November 9, 2017: My husband just learned who his birth parents are. Unfortunately both are deceased. The birth father’s family wants my husband and the last surviving sibling (an aunt) to be tested to make sure the birth mother named the right guy! I understand the test they need is called an avuncular test. Is there a specific type of lab that we can use to make sure they are testing enough and properly to try to achieve the most conclusive result, whichever way that goes? There are so many types of labs on the web...
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August 24, 2017: My sister and I did ancestry.com and she was put into a genetic community and I was not. Does this mean we are not as closely related as we think?
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