Thursday, September 25, 2014

"Understanding Autosomal Biogeographical Ancestry Results" I4GG

I could be doing a number of things as I wait for a Nurse visit ( for mom). I could have cleaned the house or microwaved IPhone. Instead I decided to listen to Doug McDonald's I4GG conference presentation titled "Understanding Autosomal Biogeographical Ancestry Results".

This was an excellent presentation. I followed his suggestion and analyzed and compared the chromosome painting charts, from GEDmatch, using my Mom, Aunt, and my own kits. My Aunt represents my deceased father's line. Comparing all of our results I have a better understanding of our results. Family Tree DNA showed substantial Eastern European roots for my Aunt. Looking at one of the charts I can clearly see she has more Eastern European than I do, that's probably why I didn't have any Eastern European at Family Tree DNA. What the tests confirmed is that we are mainly European. We can infer just a little more beyond that point. The companies still have a ways to  go in order to provide us with more than vague predictions.
Notes from Presentation:
  1. 50,000 to 300,000 markers are tested (should be to 700,000?)
  2. They're all right (tests) in the big picture
  3. Use 3rd party tools for analysis GEDMatch
  4. You may not inherit an exact 1/4 DNA from your Grandparents due to recombination
  5. At 6 to 10 generations back most of our ancestors lived in areas where their ancestors and relatives lived
  6. There is a 20% chance that you would, for instance, inherit DNA from a Native American ancestor who lived 12 generations ago.
  7. At 6 generation the probability is 100% that you have inherited some DNA from that Native American ancestor, but it can be hard to identify
  8. The tests go back at least 2000 years in time
  9. Too much overlapping of populations in Europe makes identification difficult
  10. Populations less than 500 years old are too mixed to provide useful data
  11. We should consider known probabilities; i.e., we should pick and choose which test results we accept based on what we already know about our ancestors
  12. Certain groups are easier to differentiate like Ashkenazi
  13. All companies use Monte Carlo method for best population fit
  14. Important to use demixed populations
  15. Use chromosome painting at GEDmatch to better understand and analyze your results
  16. 23andme and AncestryDNA are the best when it come to ethnic breakdown
  17. Should be 50/50 cut, in the painting, for most accurate results
  18. Only trust conservative at 23andme
  19. Look at where your strong matches come from
  20. Not enough data for Native Americans
  21. Don't trust the 3 big companies for African data they use the wrong chip
  22. Don't trust African Ancestors unless you are around 90% African
  23. Affymetrix  chip is only reliable chip for Africa
  24. AncestryDNA provided him with the best ethnic fit. He feels they have the best methodology
  25. His results skew French but his ancestors were from Scotland, which points to ancient continental ancestry
  26. Chromosome painting at 23andme very good
  27. "Fully sequence lots more people in lots more groups." "400 people each in 250 groups." Look for rare mutations shared by less than 2% overall, but common to a group
  28. Results should be analyzed by humans

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