Advanced DNA Techniques: Deductive Chromosome Mapping

Blaine Bettinger, Ph.D., J.D.
Oct 6, 2020
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Speaker's Introduction
1m 15s
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5m 10s
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DNA Inheritance
15m 50s
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How to Use
28m 52s
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Announcements / prizes
6m 50s
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Questions / answers
11m 46s

About this webinar

Chromosome mapping is typically achieved by mapping the segments of DNA we share with an identified match. In this lecture, learn how to map segments of DNA that you DO NOT share with a match! Using close relatives such as parents or siblings we can figure out where pieces of DNA came from based on lack of sharing.

About the speaker

About the speaker

Blaine Bettinger, Ph.D., J.D., is an intellectual property attorney by day and a genetic genealogist by night. In 2007 he started The Genetic Genealogist (
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  1. Legacy Family Tree
    4 years ago

    5+++ Blaine was brilliant as usual. He explains things so clearly. He makes the complex doable.

    A completely logical technique and very clearly explained. Thank you Blaine

    A great webinar from Blaine as usual but I don’t have a tester required. I thought I would listen anyway but the hour is late (US) . I will watch the video at a daytime hour. Thanks.

    A little simplistic for something advertised as advanced, but very clear.

    A real eye-opener for me! Thanks Blaine

    A very well thought out and clear presentation with explanatory example slides making it very easy to follow. Blaine, Thanks!

    A well paced and useful seminar.

    Absolutely brilliant – I can’t wait to get into this – thank you

    Absolutely brilliant webinar. This presentation makes understanding how to review DNA matches, and family connections so interesting and understandable.

    Although I do not consider myself ready for advance DNA stuff, I was able to follow and understand this lecture. Thanks!

    Always a great presenter and a topic to stretch the mind.

    Always a pleasure having Blaine educate about DNA!

    Always enjoy Blaine Bettinger. Got distracted at the end during questions and answers so I missed what he said about endogimus trees which mine definitely is.

    Always enjoy Blaine’s presentations.

    Always enjoy Blaine’s presentations.

    Always excellent!

    Always great and understandable info from Blaine. Thanks!

    Always great!

    Always learn from Blaine, Great webinar

    Always learn so much from Blaine.

    Always love Blaine’s explanations. He breaks down one simple idea and gives the tools to try something new.

    Always love Blaine’s presentations. He has a knack for making the complex simple and easy to understand. Thank you.

    Always top notch from Blaine


    Amazing information about concept of deductive dna mapping

    Amazing speaker and topic!

    Another fantastic webinar by Blaine. I’m going to be staying up late today!!!

    Another great webinar. Fortunately I was able to watch it live.

    Another great, informative Blaine Bettinger webinar. Thanks

    Another layer of knowledge. All of Blaine’s webinars are first rate!

    Another outstanding technique for tracking our ancestors using DNA! Thanks Blaine!

    Anything by Blaine is very worthwhile!

    As always Blaine is great.

    as always, blaine explain at a level expected. wonderful detail, slides and information.

    As always, Blaine gave an outstanding talk. Can’t wait to try what I have learned.

    as always, well presented and explained

    As usual a great informative and easy to follow webinar from Blaine. I am already busy using some deductive mapping.

    As usual…Outstanding presentation by Blaine…

    Best ever! Thank you Blaine- it took awhile- but now it’s all clicked in.

    Bettinger is SO clear and takes the new info step by step, returning to previous material to pound it in our heads. I will be watching ALL his webinars–and checking out his Facebook page too!

    Blain is a very good presenter. He really emphasized some critical points that otherwise might be lost on relatively new people (like me) . šŸ™‚

    Blaine always does a great job of explaining DNA concepts.

    Blaine Bettinger is hands-down one of the best DNA presenters I’ve ever watched. He explains everything so thoroughly and makes it easy to grasp challenging topics.

    Blaine Bettinger is so good at explaining his subject and I’m always so motivated to try out what he has presented. Excellent presentation.

    Blaine Bettinger is the BEST!

    Blaine Bettinger is the most knowledgeable writer, blogger and speaker in the field of genetic genealogy in the world. His presentation was excellent !

    Blaine continues to excel at presenting helpful information in an understandable and inspirational way. Thanks, Blaine!

    Blaine did an excellent job of explaining his deductive chromosome mapping technique. Would highly recommend this webinar to folks who are deeply into chromosome mapping.

    Blaine did an excellent job of explaining how to use deductive chromosome mapping.

    Blaine does an amazing job of explaining an advanced topic and making it seem like a beginner’s skill.

  2. Legacy Family Tree
    4 years ago

    Blaine explains complicated things so simply and easy to understand- my favourite presenter!

    Blaine explains everything so well, and is very easy to listen to.

    Blaine has such a clear way of explaining difficult concepts. Thank you Blaine, and thank you Geoff!

    Blaine is a pro and a blessing to all of gene-world. He brings it every time.

    Blaine is a wonderful teacher; good pace, excellent speech, patient with facts, and repeats. I am sure I will spend too much time with this new approach…

    Blaine is always an excellent presenter.

    Blaine is always good

    Blaine is ALWAYS great. This webinar was billed as “Advanced” & I expected to be out of my depth because I’ve not done chrom mapping &, despite webinars on it, I feel like I don’t fully understand it. Imagine my shock when I had no problem understanding this material.

    Blaine is always great. I also feel I took a step forward in understanding this.

    Blaine is always outstanding.

    Blaine is always wonderful

    Blaine is an amazing instructor

    Blaine is an awesome speaker. He presents difficult concepts in an easy to understand way. I learned a lot with this webinar and can’t wait to put what I learned into action.

    Blaine is an excellent instructor both in person and via webinar.

    Blaine is an excellent speaker and makes the difficult understandable.

    Blaine is an excellent teacher! I’m another one for whom the proverbial lightbulb went off!

    Blaine is an excellent teacher. Visuals were very helpful.

    Blaine is awesome. Thank you for having him on a webinar. Always learn SOOOOO MUCH!!!!!!

    Blaine is great as always.

    Blaine is great at explaining things in layman’s terms!

    Blaine is great, as always!

    Blaine is one of the best.

    Blaine is so great at explaining things in a stepwise fashion! Very helpful presentation!

    Blaine is sooo good at explaining complicated processes in a way that they’re understandable! Thank you!

    Blaine is the best!

    Blaine just has the ability to make DNA become non-threatening

    Blaine makes it sound so easy. He is clear and concise. Great presentation.

    Blaine was so easy to follow, learnt a lot, just sad that I do not have a sibling/parent/uncle/aunt I can have tested.

    Blaine, as usual, explained a potentially confusing topic in an extremely easy and digestible fashion. I will definitely be using deductive chromosome mapping in the future, probably tonight!

    Blaine’s explanations are always so clear!

    Blaine’s explanations are very clear. I enjoy every presentation.

    Blaine’s explanations were very clear.

    Blaine’s webinars are always informative and helpful.


    Can I give it a 5 ++ ? Blaine is such a clear, logical teacher! Learned some more, enjoyed it thoroughly. Thank you, Blaine

    Can’t wait to get started mapping!

    Can’t wait to try this out! Great webinar as always!


    clear description of technique!!

    Clear explanations about a fascinating and complex topic

    Clearly explained – as per Blaine’s usual excellent standard.

    Complicated but very clear presentation

    Crystal clear as usual. Excellent diagrams and example – not overwhelming number of them either.

    educational. confirmed my thinking

    Enjoy that one concept was presented and thoroughly explained – no overload!

    Even though I am just beginning my journey with Chromosome painting, I found Blaine’s presentation very clear and was able to understand the principles that he explained. Thank you




  3. Legacy Family Tree
    4 years ago

    excellent – i have 4 mapped siblings – this should be fun – thank you

    Excellent – very clear and easy to follow logic.

    Excellent as always so clear and helpful for non science people like me

    Excellent as always! Thanks, Blaine!

    Excellent content and presented in such an easy-to-understand way. Blaine is an excellent presenter. Thank you!

    Excellent explanation on a difficult topic.

    Excellent explanation. Now I need to do it!

    Excellent explanations by Blaine. He made things very clear.

    Excellent information, very well presented. I especially appreciated the visuals! Thank you!

    Excellent information.

    Excellent job – light bulb moments here too

    Excellent one of the very best.

    Excellent presentation (as expected!).


    excellent presentation and topic

    Excellent presentation by Blaine Bettinger, as always.

    Excellent presentation of an advanced subject.

    Excellent presentation! I’m going to go back to the beginning of my painting and make far better use of my siblings dna results!! Thank you!

    Excellent presentation! Blaine made a complex topic seem easy. I’ll know for sure once I apply the techniques, but I am walking away with some confidence about understanding the topic!

    Excellent presentation, it helped reinforce that I’m acutally getting it when it comes genetic DNA stuff :).

    Excellent presentation, very informative.

    Excellent presentation, very well laid out and organized.

    Excellent presentation.

    Excellent presentation. Canā€™t wait to try.

    Excellent topic and well explained

    Excellent webinar that provided many avenues for future research!




    Excellent! Getting my two sisters tested ASAP!

    Excellent! Blaine is a great presenter. Interesting and clear. Can’t wait to try this technique!

    Excellent! Thanks!

    Excellent!!!! This clarified some of my questions about the use of chromosome comparisons.

    Excellent, of course! More, please, soon! Thanks to Blaine Bettinger!

    Excellent. I appreciate how Blaine was able to so clearly explain a complex concept. Very helpful!

    Excellent. Look forward to trying this.

    Excellent. Thank you.

    Exceptionally well presented. I learned a lot. Thanks so much.

    Explained very well

    Extremely interesting


    Fabulous! Thanks Blaine. Excellent, clear explanations as usual!

    Fantastic session. Blaine has a gift for making things east to understand.

    Fantastic webinar!

    Fantastic! I just wish I had siblings willing to test and share.

    Fantastic. Definitely advanced, and glad that this was explained at the start.


    Fascinating. My sister has also tested (Ancestry) and I will have to get her to upload to GEDmatch so I can try this out. Thank you!

    Fascinating. Look forward to trying out the new learning. Thank you.

    For an “Advanced” webinar there was a lot of basic training

    Glad to see the complete focus on deductive mapping — Michelle included it in her talk (as inferred mapping) and did a good job on it, but it really needed a fully dedicated webinar — if I am not mistaken, Louis Kessler (who won best innovation at RootsTech a few years ago) was the “inventor” of this

    Good audio, well presented

    Great info so far but this is more advanced than my knowledge right now.

  4. Legacy Family Tree
    4 years ago


    Great info! I wish he showed a parent for deductive mapping!

    Great information…easy to understand.

    Great lecture and so easy to understand. Thank you.

    great material

    Great presentation. Presented in a way that was easy to understand.

    Great slides.

    Great topic. The speaker was very detailed so that everyone would understand the process.

    Great webinar as always. Thanks for organising Geoff.


    He explained it very well.

    He really does good explanations so I learn more and more about DNA.

    His presentation made me want to try the DNA printer program and also use the Deductive mapping with cousins to find out more information about our shared grandfather.

    I always enjoy Blaine’s talks and explanations about DNA!

    I always learn a ton from Blaine’s lectures, but I have to say that this one tonight really blew my mind! I’m so excited to get my siblings tested and try this methodology out! Thank you –

    I always learn something new from Blaine!

    I couldn’t stay for the whole webinar, but what I heard was great! Thanks for making it available at a good time for us in Australia.

    I don’t think of myself as an advanced dna user but decided to take the webinar anyway in hopes I might pick up something. Mr. Bettinger explained the process so systematically and logically, I’m excited to get started on my own chromosone painting.

    I enjoyed the webinar and it clarified mapping. Thank you so much.

    I feel like I discovered another piece to a puzzle. Great job of explaining it.

    I had to stop watching after about half an hour, but the webinar looks like just what I need to help me maximize what I can learn from having tested other family members. I’m looking forward to finishing the webinar once it’s in the archives. Thank you, Blaine!

    I know now that I need more relatives to do their DNA to check for matches and differences.

    I learn a little more with every webinar. DNA and chromosomes are hard for me to grasp.

    I missed a few minutes in the beginning, but overall very good! Thank you, Lisa

    I really enjoyed the examples showing application of using this Deductive Chromosome Mapping technique. Thanks!

    I watched knowing that I, as an only child with no living parents or first cousins that will test, would not be able to use this technique. However, I GET it- and maybe I’ll be able to help others in my genealogy group use it. Blaine is always an excellent presenter- he knows how to break a subject down and keep adding just a bit more so you really can understand. By the end, a complex topic is now understandable.

    I would give it a higher rating if possible. Excellent!

    I’d rate him a 10 if I could!

    I’m actually just still starting with DNA, but I still learned a lot in terms of the windows that DNA mapping can open. Fabulous class – everything so thoroughly explained that even I grasped the concepts! Thank you!

    In-depth, knowledgeable, with lots of presentation materials to break it down which made it comprehensible.

    Interesting info and presented very well.

    Is there any way I can give this webinar a rating of 10?

    It is interesting that for DNA Painter, Jonny says not to use siblings; however, that is exactly what you need for this type of chromosome mapping. Very interesting to think there is often more information than we know right in front of us.

    It is time-consuming to state things clearly, but glad Blaine does it that way.

    It makes perfect sense what Blaine explained. Iā€™ve worked with DNA painter a bit but am unsure on how it will move my search for ancestors forward

    It was a very good presentation and Blaine explains it so well. The suggestion to draw it out will help to prevent confusion. I’m eager to try this!

    It was great to have a webinar on advanced DNA techniques.

    It was great. Can’t wait to try what was taught!

    It was indeed a light bulb moment. Thanks, Blaine.

    It was very helpful to me. The description could have mentioned that it is useful only when you are certain of the relationship of the match.

    I’ve done Visual Phasing so this was great to see how to actually use the Deductive process. I’ve thought I could do it but now know how to do it properly. Thanks Blaine for another exremely well explained and clearly demonstrated process to add to my DNA kit!

    I’ve had a eureka moment or two during this webinar. Blaine at his finest.

    I’ve heard the concept, but it was a good visual to help with the explanation.

    just great, thank you

    Looking forward to more DNA webinars on the Advanced Level!

    Lots more to learn

  5. Legacy Family Tree
    4 years ago

    Love getting taught by Blaine. He is one of my favorite presenters, and this explanation of Chromosome Mapping was excellent. Thanks Blaine.

    Love those light-bulb moments! Thanks!

    Loved the advanced level of utilizing DNA

    Makes use of those black spaces that I never thought about before. Thanks, Blaine.

    mind blown! great info…keep it coming!

    Most helpful webinar on DNA I’ve ever watched. Can’t wait to test my sister!!

    My mind was blown! Blaine Bettinger makes a complicated process feel so simple! He gives me hope that I can use my DNA matches to figure out my great grandmother’s side of my family tree!

    Never a disappointment with Blaine Bettinger!

    New advanced technique, well explained by Blaine.

    Now I have a name for something I’ve been doing for a long time. I’m a very logical person though so I figured it out on my own.

    One of the best !

    One of the best on Genetic Genealogy I’ve seen, ever. So glad I’ll be able to view it again, as a (long time) Legacy Webinar subscriber. Thanks to both Legacy Webinars and Blaine T Bettinger.

    One of the best webminar I had here yet! Thanks to Blaine!

    Organized, logical and to the point. I was waiting for someone to explain relationships and mapping your grandparents dan using your siblings. Thank you Blaine”

    Outstanding session!!!



    Really enjoy Blaine’s presentations.

    Really enjoyed this, thank you!

    Really nice to remember to watch one live. This year is my 3rd year for membership. It is such a benefit- I cant always make a conference – but I can learn new things with the webinars.

    Received valuable information for my research. Thank you!

    Simple – not to broad a subject like some are. I could understand the concept as it was explained in detail.

    Simple and easy to understand. Thanks!

    Simple, clear, concise explanation of deductive mapping with two examples… loved it!

    So clear. Blaine made a difficult subject easy to understand.

    So pleased I was on holidays and could view very useful.

    So well done. Even tho’ I haven’t spent a lot of time on chromosome mapping, Blaine did such a good job explaining his deductive mapping, that I was able to understand it easily. Thank you!

    Speaker kept his presentation simple and too the point.

    Stupendous presentation-clear and concise!

    Succinct, concise, and clear! A great way to break down an advanced topic!

    Such a complex topic but Blaine explained it so clearly. Tomorrow I will give it a try!


    Super and I actually understood it.

    Superb—need more like this.

    superstar with great information and presentation!


    Thank you- very informative!

    Thank you!

    Thanks Blaine for a wonderful webinar. As usual, you explain even difficult topics with amazing clarity. I’ve been trying to get my head around this topic for ages, but now I feel confident that I finally understand it! Can’t wait to start mapping deductively!!

    Thanks Blaine. Awesome webinar – very clear. You make a complex topic understandable. Thanks Legacy for providing these webinars!

    The concept of deductive chromosome mapping finally makes sense to me. Thank you, Blaine B!

    This is amazing stuff! And Blaine, as always, explained it so well.

    This was a lightbulb moment for me!

    This was a very good intro to deductive chromosome mapping. I would like to know applications of how to use this info and also to know if you can use the info to expand/broaden beyond one generation? Thanks!

    This was great!

    This was great. Very clear and informative.

    This webinar may help me to finally differentiate dna between my deceased parents that I was unable to test. As usual, Blaine has demystyfied DNA so a lay person can better understand. Thanks Blaine and thank you Legacy Webinars for continuing to bring great educational programs for better research techniques.

    This webinar was very enlightening and informative. Very, very helpful in comparing sibling & cousin DNA differences. Blaine explained the process in a way that was easy to comprehend.

    top notch

    unbelievable good!

    Unfortunately came in just at the end–looking forward to the replay tomorrow! Good night, everyone!

  6. Legacy Family Tree
    4 years ago

    Very clear and concise. I actually followed!! I’m anxious to try it on my own.

    Very clear explanation of topic. Thank you for offering free webinars.

    Very clear presentation! Thank you Blaine.

    Very clear presentation. Thanks, Blaine!

    Very clear speaker.

    Very clear, reinforced concepts which is excellent since I did get confused between maternal/paternal

    Very clear, step through. Only additional information I would like would be using a match to a second cousin.

    Very clear, thank you!

    Very clearly explained as usual.

    Very clearly presented!

    Very clearly spoken, and each piece of information was clearly explained before moving on. Excellent presenter.

    Very detailed and this about my 4th webinar about this subject

    Very easy to follow.

    Very good and useful info but presentation was overly repetitive.

    Very good explanation. Easy to follow.

    Very good information we will be able to use. Thank you!

    Very good, clear instruction. Liked it a lot!

    Very good, Would appreciate a bit more depth. Would enjoy a webinar with both visual phasing and deductive mapping used concurrently and cross referenced. It was just a tiny bit slow going. So 4.5 would be my real rating.

    Very helpful! Thanks!

    Very illluminating!

    Very informative and helpful. Thank you!

    Very informative and I got it totally. Can’t wait to apply it.

    Very informative with easy to understand examples – Thank you!

    Very informative! Blaine is always excellent! Thanks!

    Very informative! I always learn valuable tips and techniques from any of Blaine’s lectures.

    Very informative, going to give it a go today. Thank You

    Very informative. Anxious to try it.

    very interesting a lot was covered

    Very interesting! Thank you!

    Very interesting.

    Very interesting.

    Very interesting…. perhaps a little advanced for me but definitely added to my understanding of utilization of DNA matches

    Very precise examples and the speed at which Blaine spoke made it an informative session

    Very stimulating presentation, great to have my understanding of this subject clarified, thanks, Blaine.

    Very Understandable

    Very useful although I am still at beginner stage

    very useful technique very well explained

    very well explained

    very well presented !

    Wasn’t as advanced as I expected, having already done visual phasing,

    Watched this because of Blaine!!

    We always get better insight into DNA from Dr. Bettinger. And he makes it so easy to understand. Thank you very much.

    Well explained – I’ve found a new way to occupy hours of my day

    Well presented and easy to understand. Thank you!

    well presented!

    What a fantastic step forward — it is great that an advanced session is being presented in clear terms but without having to cover basics.

    What I enjoy about Blaine’s webinars is that he doesn’t teach at the lowest common denominator level. He is brilliant, what else is there to say?


    wonderful and Blaine’s explanations are clear and easily understood

    Wonderful information!

    Wonderful, wonderful webinar of using Deductive Chromosome Mapping. The light did come on for me also.

    Wow! Anxious to get started!

    Wow, I learned a lot!

    Wow. Just wish my parents and siblings were alive to collect DNA from so I could map them


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