Walter Steets Houston Genealogical Forum DNA Interest Group February 24, 2018

Transcription

1 Using Ancestry DNA and Third-Party Tools to Research Your Shared DNA Segments Part 2 Walter Steets Houston Genealogical Forum DNA Interest Group February 24,

2 Today s agenda Brief review of previous DIG session Displaying Ancestry Shared DNA using MedBetterDNA Ethical and legal issues for the family genetic genealogist GEDmatch tools Are Your Parents Related One-to-many A-Matrices Chromosome browser One-to-one DNA Painter Chromosome browser which displays phased chromosome data and labels for each segments Display of shared DNA and relationships using McGuire Diagrams 2

3 MedBetterDNA Enhanced DNA Reports in Ancestr y MedBetterDNA Extension for Chrome web browser which only works with Chrome Can be installed from Chrome Web Store for free. Search for MedBetterDNA Without this extension, the Shared Matches page displays only single Notes With the extension, the Shared Matches webpage can display all Notes simultaneously The extension can also filter on Ancestry stars or on hashtags placed in notes. 3

4 Informed Consent and Beneficiary Forms In the last session we discussed several questions concerning our obligations and rights as family genetic genealogists with respect those we ask to take DNA tests. In the past week, Blaine Bettinger s has addressed these issues in his blog post Informed Consent Agreement and Beneficiary Agreement which includes: Informed Consent Agreement Model agreement giving genealogist certain rights to use results of test-takers DNA results Also used to inform test taker of possibility of unexpected results and ask whether he wants to be informed of them Beneficiary Form Model agreement defining what happens to DNA results in the event of the death of the DNA test-taker. Can address situations such as what happens to a test-taker s results if they die and the genealogist paid for the test. 4

5 DNA Data Transfer Process AncestryDNA.com GEDMatch.com Are Your Parents Related One-to-many matches Autosomal Matrix Comparison 2-D Chromosome Browser One-to-One Comparison DNAPainter.com Paint a New Match using data copied from GEDMatch Ancestry Raw Data File Copy of GEDMatch Oneto-One Comparison table 5

6 GEDmatch Tool Set 6

7 Are Your Parents Related? Effect of Closely Related Parents on Genetic Analysis May not be able to distinguish paternal from maternal cousins. Both chromosomes in a chromosome pair can have segments from the same ancestor. Genealogical paternal cousins can match maternal cousins if they share DNA segments from the ancestor common to the parents. Relationship estimates based on the total amount of shared DNA may be too close Shared DNA may include contributions from more than one ancestral line increasing the amount of shared DNA Check the possibility that your parents are related using the GEDmatch Are Your Parents Related? tool. 7

8 GEDMatch One-to-many Matches Displays DNA kits matching a base kit. Comparable to Shared Matches in Ancestry. Kit Nbr Identifier for DNA Raw data sets loaded into GEDMatch. First letter indicates testing company Select allows matches to be selected for chromosome or matrix comparisons Details clicking on A displays one-to-one list between base kit and A row kit Total cm total shared cm Largest cm length of single largest shared segment Gen GEDMatches estimate of the number of generations between MRCA and match Example: DNA matches to Kit M Sharron 8

9 Paternal Paternal Paternal Paternal Paternal Paternal GEDMatch: Sharron s Autosomal Matrix for Closest Matches 10

10 GEDMatch: Sharron s Matches 11

11 The origin of IBD segments is depicted via a pedigree of 12 individuals. Segments which are Identical by Descent (IBD): Example of 1 st Cousins Each box (male) and circle (female) represents a chromosome pair for the named person. For example, bars could be the chromosome pair for chromosome 1. Due to crossing over, offspring inherit recombinant chromosomes of their parents. The first order cousins in the bottom row, Karen and Louis, share one IBD segment (borders marked by grey lines). Both have inherited this IBD segment from the same individual, namely their grandfather Carl (orange colored chromosome in the top row). Albert Bertha Carl Donna Edward Fiona Gregory Helen Ian Janice Karen Louis Adapted from Gklambauer, Wikimedia Commons 13

12 GEDmatch Chromosome Browser These matches share a segment from a common ancestor who is not an ancestor of norapru8 14

13 GEDmatch Chromosome Browser Norapru8 shared this segment from a common ancestor with Sharron s close relatives but not more distant ones. 15

14 GEDMatch One-to-One Comparison Tool Provides detailed information for each DNA segment shared between two kits Chr chromosome number Start Location starting location in megabase pairs (Mb) End Location end location in megabase pairs (Mb) Centimorgans amount of shared DNA in cm SNPs number of single nucleotide polymorphisms contained in segment This data is copied and pasted into the DNAPainter chromosome browser. Comparing Kit M (Sharron ) and T (SD) 16

15 DNAPainter.com 17

16 DNA Painter DNA Painter allows you to display phased and labeled shared DNA segment data. Individual segments may be labeled by MRCA ancestor may help to identify unknown matches 18

17 Painting a New Match into DNAPainter Copy the GEDmatach one-to-one web page by pressing ctrl-a and then ctrl-c Open the Paint a Match page in DNAPainter Copy the one-to-one results into DNAPainter by pressing ctrl-v 19

18 Questions? 22