Visual Phasing: An Example (Part 5 of 5)

Five-Part Series on Visual Phasing:

In “Visual Phasing: An Example (Part 1),” we identified and labeled all of the recombination points in the three siblings, Susan, Brooke, and Felix. Then, in Part 2 of the series, we used the identified and labeled recombination points to assign segments of DNA to the four grandparents (the blue grandparent and grey grandparent pair, and the purple grandparent and green grandparent pair). In Part 3 of the series, we used cousin matching to identify the grandparental source of the chromosomal segments. And finally, in Part 4 of the series, we characterized my paternal chromosome.

After Part 3, we had the following for Brooke, Susan, and Felix:

step4g

Now that we have this information, let’s see if we can use that to explore new matches with Brooke, Susan, and Felix.

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Visual Phasing: An Example (Part 4 of 5)

Five-Part Series on Visual Phasing:

In “Visual Phasing: An Example (Part 1),” we identified and labeled all of the recombination points in the three siblings, Susan, Brooke, and Felix. Then, in Part 2 of the series, we used the identified and labeled recombination points to assign segments of DNA to the four grandparents (the blue grandparent and grey grandparent pair, and the purple grandparent and green grandparent pair). In Part 3 of the series, we used cousin matching to identify the grandparental source of the chromosomal segments. After Part 3, we had the following for Brooke, Susan, and Felix:

step4g

Since Felix is my father and Susan and Brooke are my aunts, I might be able to compare my DNA to my aunts in order to identify which of the segments I obtained from my father.

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Visual Phasing: An Example (Part 3 of 5)

Five-Part Series on Visual Phasing:

In “Visual Phasing: An Example (Part 1),” we identified and labeled all of the recombination points in the three siblings, Susan, Brooke, and Felix. Then, in Part 2 of the series, we used the identified and labeled recombination points to assign segments of DNA to the four grandparents (the blue grandparent and grey grandparent pair, and the purple grandparent and green grandparent pair):

step4b

But without more information, we don’t know to which grandparent each segment belongs.

Today, we’ll use cousin matching (defining “cousin” to mean anyone other than the siblings) to first identify the maternal pair of chromosomes, and the paternal pair of chromosomes. Hopefully, in the process, we’ll be able to assign the segments to each of the four grandparents, rather than just maternal/paternal.

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Visual Phasing: An Example (Part 2 of 5)

Five-Part Series on Visual Phasing:

In “Visual Phasing: An Example (Part I),” we identified and labeled all of the recombination points in the three siblings, Susan, Brooke, and Felix:

step-3a

In Part 2 of the series, we’ll use the identified and labeled the recombination points to assign segments of DNA to the four grandparents.

Step 3 – Fill in Chromosomes

The next step is to fill in the chromosomes using the identified recombination points. We’re going to start with the fully identical region shared by Susan and Brooke, shown in the red square in the next image. We can fill into both chromosomes for Susan and Brooke (the blue and purple segments):

step-3b

Each of the blue and purple segments is one of the following segments: (i) paternal grandfather; (ii) paternal grandmother; (iii) maternal grandfather; or (iv) maternal grandmother. We’ll try to figure out which is which later.

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Visual Phasing: An Example (Part 1 of 5)

Five-Part Series on Visual Phasing:

  • Part I – Explaining visual phasing and identifying/labeling recombination points (November 21, 2016)
  • Part II – Assigning segments of DNA (November 22, 2016)
  • Part III – Using cousin matches to identify which grandparent provided the segments
  • Part IV – Mapping my own chromosome using the visually phased paternal chromosomes
  • Part V – Using the mapped DNA with new matches

This weekend, I spoke at a meeting of the New England chapter of the Association of Professional Genealogists, and it was a wonderful group. One of my talks was about “Chromosome Mapping.” Unfortunately, since the talk was only an hour, we didn’t have time to discuss “Visual Phasing,” a chromosome mapping methodology. Instead, I promised to finish this blog post to explain the process. As I was writing, the blog post turned into a 5-part series!

Quick Summary

  • What is it? A method to assign segments of DNA to the test-taker’s four grandparents.
  • Why use it? To identify which grandparent gave the test-taker which segments of DNA (eliminating 75% of the family tree to search for MRCA).
  • What do you need? Autosomal DNA of three siblings uploaded to GEDmatch.

Visual Phasing

Visual Phasing is a process by which the DNA of three siblings is assigned to each of their four grandparents using identified recombination points, without requiring the testing of either the parents or grandparents. Although the process does not automatically reveal which segment belongs to which of the four grandparents, matching with cousins provides this identification as a further step of the process.

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Announcing “The Family Tree Guide to DNA Testing and Genetic Genealogy”

s7981_new01I am so happy to officially announce “The Family Tree Guide to DNA Testing and Genetic Genealogy,” my effort to help people understand DNA and genetic genealogy. The book, published by Family Tree Books, is 240 pages long and covers every aspect of DNA testing for ancestry research:

  • Part One: Getting Started – Genetic Genealogy Basics; Common Misconceptions; and Ethics and Genetic Genealogy
  • Part Two: Selecting a Test – Mitochondrial-DNA (mtDNA) Testing; Y-Chromosomal (Y-DNA) Testing; Autosomal-DNA (atDNA) Testing; and X-Chromosomal (X-DNA) Testing
  • Part Three: Analyzing and Applying Test Results – Third-Party Autosomal-DNA Tools; Ethnicity Estimates; Analyzing Complex Questions with DNA; Genetic Testing for Adoptees; and The Future of Genetic Genealogy
  • Appendices – Comparison Guides; Research Forms; and More Resources

For a preview of the book, you can visit the Amazon page or Google Books.

As you’ll see, the book is full of color images that help explain all aspects of DNA and genetic genealogy, like the following (only a portion of each are shown):

siblings

flowchart2

Here are a few reviews of The Guide:

You can also hear me talk about The Guide on Episode #8 of The Genealogy Connection with Drew Smith.

The book is available for purchase at the following:

And, if you’ve purchased and read The Guide, please consider leaving a review at Amazon!

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Second Cousins (Or Closer) That Don’t Share DNA?

Caution should always be taken before pursuing an answer to a genealogical question. Ask yourself (or your relative) before diving into the research whether you really want to know the answer, and whether you think you are prepared for it. Just because you as a genealogist may be prepared for the result does not mean everyone in your family will be.

This is as true with DNA evidence as it is with any other type of genealogical evidence. Just as a census record or birth certificate can reveal a family secret, so can the results of a DNA test. The Genetic Genealogy Standards, for example, make clear that unexpected results can occur:

12. Unexpected Results. Genealogists understand that DNA test results, like traditional genealogical records, can reveal unexpected information about the tester and his or her immediate family, ancestors, and/or descendants. For example, both DNA test results and traditional genealogical records can reveal misattributed parentage, adoption, health information, previously unknown family members, and errors in well-researched family trees, among other unexpected outcomes.

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Genetic Genealogy and Native American DNA

[EDIT (7/6/2016): Razib Khan discusses the same issue here.]

I despise all politics. I suppose someone has to do it, but I always do my best to avoid discussing it either in person or online. I consider it to be a huge success when people don’t know my political leanings (is “away from all politics” a political leaning?).

Currently, however, there is a political figure who potentially has asserted that he or she might have distant Native American ancestors (specifically, Cherokee ancestors). For no real reason other than politics, some have disputed the claim, and the media is actually writing stories about it. Trust me, this whole ‘debate’ surrounding one person’s ancestry is so unbelievably unimportant that you don’t want to waste your time to look it up.

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Update to the Shared cM Project

[EDIT: PDF edited on 31 July 2016 to correct the averages for 1C and 1C1R (hat tip to Andrew Millard, thank you!)]

The Shared cM Project is a collaborative data collection and analysis project created to understand the ranges of shared centimorgans associated with various known relationships. As of June 2016, total shared cM data for more than 10,000 known relationships has been provided.

This is the first update to the original data, released in May 2015. In this update there are more than 4,000 new entries. Additionally, the data for each relationship has been analyzed statistically to remove extreme outliers and produce a histogram to show the distribution.

For more information see The Shared cM Project page, and “Autosomal DNA Statistics” page at the ISOGG Wiki. HERE is the link to provide your data for future updates.

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Charging for (Genetic) Genealogy Services

wordcloudIn our culture and economy, we place a value on the goods and services that we create or offer. Since others may not have the time or ability to create those goods or services themselves, we sell what we create to others in order to earn money. As we improve upon those goods and services, it becomes increasingly hard for others to replicate them, and thus the value increases. Similarly, as the demand for those goods and services increases, the value increases.

Unfortunately, the services offered by genealogists, including genetic genealogists, are severely undervalued in our culture. One of the most common explanations is that genealogy is a hobby and therefore subscriptions and research services are an unnecessary expense, and/or that people only use “disposable income” for genealogy. (Don’t say that outloud at a genealogy conference!).

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