Ralph Caspers wonders where he comes from and whether a DNA test could tell him more about it. A DNA test like this to determine origins is not particularly complicated. It does not even require the entire genome to be analyzed: it is enough to look closely at the places that are known to differ between people. That is only about 3 percent of our genetic material. This means that 97 percent of our genetic material is identical in all people! But the other three percent make up over 90 million places in the DNA. And that is where the DNA test looks for mutations. The pattern of these changes is then compared with the pattern of changes in other people who have also had their genetic material examined. Simply put: the more similar the patterns are, the more closely related you are to one another and therefore the more similar your origins are. However, the genetic material is not passed on to descendants according to a simple mathematical formula - i.e. a quarter from grandma, an eighth from great-grandma, etc. - but is thoroughly mixed and reassembled when sperm and egg cells are created. Therefore, it is entirely possible that you may have a distant ancestor from Japan or Nigeria, but that by chance all of this ancestor's genetic material was lost when the cells were reassembled. And there is another, very big difficulty for providers of DNA tests to determine origins: people very rarely stay in the same place for many generations - mutations can therefore spread very quickly across the whole world. As for Ralph's personal ancestors: at the time of Charlemagne, he had 1,099,511,627,776 ancestors. Purely mathematically. Ralph explains in the video what this number says about the accuracy of DNA tests for origins. Chapter 0:00 Intro 1:22 How do you do a DNA ancestry test? 3:21 What do DNA tests examine? 5:27 How accurate are the details of origin in DNA tests? 8:02 Are all people related to one another? Authors: Ingo Knopf, Ralph Caspers Editing and graphics: Klaus Wache Sound design: Klaus Wache Editor: Wobbeke Klare Reading tip Current overview on the topic: Genetic similarity and genetic ancestry groups; PDF: https://gcbias.files.wordpress.com/20... Our most important sources A global reference for human genetic variation; in: Nature, 2015 https://www.nature.com/articles/natur... Genotype Concordance and Polygenic Risk Score Estimation across Consumer Genetic Testing Data; in: Annals of Human Genetics, 2020 https://onlinelibrary.wiley.com/doi/1... A variant-centric perspective on geographic patterns of human allele frequency variation; in: eLife, 2020 https://elifesciences.org/articles/60107 Recent Common Ancestors of All Present-Day Individuals; in: Advances in Applied Probability, 1999 http://www.stat.yale.edu/~jtc5/papers... How Much of Your Genome Do You Inherit from a Particular Ancestor? in: gcbias (blog), 2013 https://gcbias.org/2013/11/04/how-muc... The Probability That Related Individuals Share Some Section of Genome Identical by Descent; in: Theoretical Population Biology, 1983 https://www.sciencedirect.com/science... Consistency of Direct to Consumer Genetic Testing Results Among Identical Twins; in: The American Journal of Medicine, 2020 https://www.amjmed.com/article/S0002-... A Historical-Genetic Reconstruction of Human Extra-Pair Paternity; in: Current Biology, 2019 https://www.cell.com/current-biology/... Recent advances in the study of fine-scale population structure in humans; in: Current Opinion in Genetics & Development, 2016 https://www.sciencedirect.com/science... Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis; in: Nature Communications, 2010 https://www.nature.com/articles/ncomm... Did you like the video? Then subscribe now to the official Quarks channel with Ralph Caspers @DimensionRalph on YouTube! Also visit the official Quarks channel on YouTube: @Quarks #quarks on Instagram: / quarks.de Quarks on Twitter: / quarkswdr Quarks on Facebook: / quarks.de #dna #dnatest #herkunft #dimensionralph