Armchair Genealogy
By
Melinda Cohenour
Exploring The Chromosome Painter
A couple months ago, this column focused on the latest "bells and
whistles" offered by Ancestry in connection with its DNA test results.
One of those new features was the Chromosome Painter. Your author
declined to expound on this feature as only a very cursory exploration
was undertaken. This month we shall take a closer look.
HOW TO FIND THE CHROMOSOME PAINTER:
First of all, it almost seems as though Ancestry chose to tuck
this tool away to be found by only the most ardent search. No
application title for this Chromosome Painter is to be found on the
drop-down list that appears after one clicks the three parallel lines in
the upper left corner on the initial screen. As the application
pertains to the distribution of meaningful chromosomal data, logic
dictates the tool would appear as a subtitle in the DNA section. That is
not quite the case, however.
Do click the three parallel bars to reveal the first level
options that appear. NOW click on DNA STORY. The next screen displays
your most recent Ethnicity Estimate (which changes each time Ancestry
updates their computer algorithms to encompass all the data derived from
the millions of new tests furnished by its latest testing customers).
We're getting close now, but Ancestry still does not give us a
quick click path to our goal. One must now scroll down to where is
found NOT a title for Chromosome Painter BUT an invitation to COMPARE MY
DNA beneath the introductory section reflecting BETA "Compare with
matches" that also reflects profile icons or portraits of YOU and two of
your closest DNA matches.
Well, that's intriguing but WE HAVE NOT FOUND THE CHROMOSOME
PAINTER YET. Keep scrolling, leaving that fun challenge behind for the
moment. Beneath that hyperlink we find in BOLD TYPEFACE the title for
"Ethnicity Inheritance" - and beneath that "Your regions inherited from
each parent."
THE PIE CHART
Looks like we're getting somewhere. Next is displayed the pie
chart labeled at the top YOU and on the left half "Inherited from
Maternal" and on the right half "Inherited from Paternal". This
helpfully provides the Sideview Technology breakdown Ancestry's new
technology utilizes to divide our chromosome data into that portion
inherited from each parent by examining information gleaned from test
subjects' responses as to how Shared Matches are related. The
computer(s) now re-sort those Shared Matches by Maternal and Paternal
based on your selections.
Each person has 23 chromosomes, 22 pairs called autosomes,
and one of which is referred to as the sex chromosome because this pair
of chromosomes determines your gender at birth. The Maternal 23rd
chromosome always furnishes an X. The determinant for gender, however,
comes from daddy. If the Paternal 23rd chromosome is marked with X,
you're a girl (23rd PAIR reads X X). If it's a Y, you're a boy (23rd
PAIR reads X Y).
For determining ethnicity only the remaining 22 pairs are
utilized. These are sorted by length of coding per pair, longest to
shortest. Sideview Technology has been used to divide these lines of DNA
by Parent 1 and Parent 2. Ancestry's computers can attribute the
distinct coding to the two parents but cannot determine which is
Maternal and which is Paternal. That was left for you to determine based
on your knowledge of where momma and daddy's families originated using
old fashioned document based research.
Further, the computers will compare the strings of coding
resident in each chromosome to Ancestry's Reference Panel to pinpoint
the ethnic origins of each segment. What is a Reference Panel? Let's
use Ancestry's explanation:
What is a reference panel?
A reference panel is a set of people whose DNA is typical of DNA
from a certain place—people native to a place or group. To make it into
the Ancestry DNA reference panel, people need two things: a paper trail
that proves their family history, and DNA confirmation of their
ethnicity. Their DNA is what your DNA is compared to when you take an
Ancestry DNA test.
To estimate your ethnicity, we find the reference panel
DNA that's most similar to each segment of your DNA. Then, we assign
your segments to the regions they resemble. For example, if a piece of
DNA is most similar to the reference panel DNA from Tonga, that segment
will go into the "Tonga" bucket.
Our reference panel has 68,714 DNA samples that divide the world into 84 overlapping regions and groups.
CHROMOSOME PAINTER VS. CHROMOSOME BROWSER
There is a difference. Ancestry says:
How is a chromosome painter different from a chromosome
browser? Chromosome painters display your ethnicities across your DNA
and show which ethnicities came from each of your biological parents.
This is different from a chromosome browser, which displays
segments of identical DNA shared by two people. Chromosome browsers are
mainly used to figure out relationships to genetic relatives and to link
pieces of DNA to specific ancestors.
But what if we want to determine who shares segments of identical DNA?
Again, Ancestry has an answer:
We do not currently have a compare feature, but if you and a
match compare your results yourselves, you may find regions where you
share the same ethnicities. If you do, this does not mean you have
identical DNA at those places–only that you have the same ethnicities
there.
Aaah. YES! Finally we can begin to explore the Chromosome Painter. Remember, we clicked the three parallel bars (top left on your screen) to reveal a listing of options.
We selected DNA and in that section clicked on DNA Story. That
selection opened to reveal a screen with a text bar appearing beneath a
world map. That text bar reads Ethnicity; Inheritance; Communities; and
Matches.
Beneath that world map on which appear areas filled with colored
sections (Hint: those are your geographic representations of your ethnic
origins), is a headline reading Ethnicity Estimate. Below that is the
listing of your ethnic origins. DON'T GO THERE JUST YET.
Go back to the text bar above and click on the word INHERITANCE.
Ethnicity Inheritance now shows a sequence of informative displays:
-
Ethnicity Inheritance. Your regions inherited from each parent. The PIE CHART.
- The Chromosome Painter. DON'T GO THERE YET.
- View breakdown. CLICK THIS HYPERLINK.
BREAKDOWN:
Here we are provided a series of supporting factotum:
-
THE PIE CHARTS which display your ethnic origins inherited from
Maternal and Paternal contributions. A second PIE CHART displays YOU and
cumulates the Maternal and Paternal contributions to show how those
combined reflect your percentage for each ethnic origin.
- A Detailed Comparison that illustrates how each geographic
area represents the amount contributed by Maternal PLUS the amount
contributed by Paternal which, added together, creates your total
percentage for each ethnic group.
- Explanatory sections to provide information (Inheritance is
Random; Their halves Your whole; How do we know this-Sideview
Technology; Matches split by parent; and FINALLY Chromosome Painter with
an invitation to Explore Now).
Chromosome Painter: THE BAR CHART
ANCESTRY SAYS: Where are your ethnicities in your DNA? With
the chromosome painter, you can see for yourself. We’ve “painted” your
chromosomes (the colored bars below) with the regions they’re associated
with in your ethnicity estimate. Select an ethnicity to see it
highlighted. Choose Maternal or Paternal to see which chromosomes were
passed down by whom.
The Bar Chart displays the 22 autosomal chromosomes numbered from
1 to 22, each numbered chromosome made up of TWO bars, representing one
for Maternal contribution and one for Paternal contribution. You will
see the longest stretch of DNA appears in Chromosome 1, and graduates
sequentially to the shortest segments of DNA depicted in Chromosome 22.
Each set of rows are "painted" with colors representing
geographic areas that correspond to the colors used to represent
specific ethnic / geographic origins.
Just above the Bar Chart appears the word Regions. Beneath that
word is a row of elliptical words: All (clicking that displays all the
colors on all the rows in the entire chart), then separate words
defining each ethnicity Ancestry has determined to make up your ethnic
inheritance. For instance, mine shows first SCOTLAND. Clicking Scotland
closes the All category and now displays where on each row segments of
DNA match the Reference Panel to indicate Scottish origins. A bright
green 💚 fills in portions of each chromosome number containing such
DNA, clearly reflecting Maternal and Paternal contributions. Since my
Ethnicity Estimate currently reflects 48% of my DNA to be derived from
Scottish ancestors on both sides, large portions of these bars contain
green paint.
Clicking on my next largest percentage ethnic group (Ireland)
does not close the Scotland group. One must manually click Scotland to
close that and reveal only the DNA for Irish ancestors. And, so on for
each ethnic origin displayed. If you wish to display more than one
ethnic region at a time merely leave the category open. You can pick and
choose as many ethnic origins as you wish.
One could say the PIE Chart cumulates the DNA contributions of
our parents while the Chromosome Painter BAR Chart distributes those
contributions across the paired 22 autosomal chromosomes.
Lastly, Ancestry responds to some Frequently Asked Questions:
FAQ
How can I use this information?
With this data, you can get a general feel for how recent
your connections are to your ethnicity regions. The longer a segment (a
single colored block) is for a region, the more recent your connection
to that region may be.
What are chromosomes?
Chromosomes are bundles of DNA in your cells. Most people
have 23 pairs. In each pair, one chromosome came from one parent, and
one came from the other. The chromosomes that have the most to say about
your ethnicities are your 22 autosomes (your non-sex chromosomes), so
that’s why we’re only showing you these 22 chromosomes.
What if a match and I have the same ethnicity in the same spot?
If you and a match have the same ethnicity in the same
location on a chromosome, it doesn’t mean your DNA is identical there.
You can have the same ethnicity in the same place, but from different
patterns in your DNA. With the chromosome painter, it’s not possible to
tell where you share DNA with someone.
If your query was not answered, click Read More to reveal an expanded list of FAQ and responses.
After you have explored the Chromosome Painter, it would be
fun and informative to go back to the section mentioned in the very
beginning of this tutorial titled Compare with matches, marked BETA
including a hyperlink COMPARE MY DNA beside profile pics of you and
(probably) your two or three closest DNA matches.
This is an area that promises to be of greater value for
those of us seeking to identify "missing ancestors". You know, those
aggravating gaps in our lineage where a grandfather should appear? Worse
yet, as in my children's lineage their paternal grandmother. Their
father, my first husband, was abandoned at birth by his birth mother,
handing her infant son off to the Miami-Dade Children's Home, a
community orphanage.
Florida is one of the toughest states for unlocking birth
records for adoptees. For my first husband was adopted about age three.
His adoptive mother yearned for naturally conceived and born babies but
as a result of an early trauma (she did not fully disclose to me), was
unable to. Thus, she adopted Johnny and, later, his sister Ann. She
tried hard to conceal that her children were adopted. Easy with Ann
because she was a newborn when taken from the hospital by her biological
father and Johnny's mother who were later married. But Johnny was old
enough to recognize the faked pregnancy tricks employed by their mother.
Especially when as a teenager he happened to walk in where his mom was
positioning the pillow she used to simulate a late term baby bump.
Even confronted about her pseudo pregnancy, his mom refused
to acknowledge and explain. This caused Johnny to reflect on the
inconsistencies in his memories and the inadequate explanations
supplied. He first began to question the truth of his own origins. It
would be the bothersome "thorn in his soul" that would cause him torment
the rest of his life. I vowed to him that I would do all I could to
reveal the truth of his ancestral past. I still pursue that truth today,
not just for my first love but for his children and grandchildren and
their descendants as well.
And this new BETA tool might help to identify that long lost
woman who desperately sought to conceal her connection to that precious
infant.
My daughter, Johnny's child, and her nephew, the son of her
older brother have had their DNA tested. The results have revealed half
siblings fathered by Johnny. By using this tool to compare UP TO TEN DNA
MATCHES at a time, we may be able to close in on that mystery mother.
HOW IT WORKS
The comparison screen is in a spreadsheet format. Column headings
are populated by the names of those whose ethnic makeup are to be
compared. The default first column is, as would be expected, your name
or if the comparison is being done on behalf of another, that person's
name. Columns to the right will contain the names of up to ten matches
whose results you wish to compare.
The next data appearing below references the ethnic
geographic occupying the greatest percentage. Since I have chosen to use
my daughter's profile to possibly zero in on Johnny's Mystery Mom, this
area is England and Northwestern Europe. Melissa's percentage 38%. We
have identified a family of close matches - a mother (probable 2nd
cousin), her son, daughter, grandson and possible other relatives who
have no tree attached to their tests but share a surname and are Shared
Matches. In addition I have chosen to include Melissa's two closest half
siblings.
Honestly, I don't yet know what the data is telling me. I can
see the daughter inherited more of this ethnic group from her father
because her percentage is greater than her mother's. The percentage
total for a child is the percentage contributed by the mother plus the
percentage contributed by the father.
I can draw no conclusion as to the relationship of the Shared
Matches with the same surname since siblings can inherit widely
disparate amounts or segments of DNA from their parents.
For now, this Comparison tool is of interest but not
extremely informative. It will require more study to determine how or IF
it can be used to confirm the suspected identity of Mystery Mom.
This has been a fun yet frustrating exploration of the
Chromosome Painter and related applications dreamed up by the scientists
and researchers at Ancestry. More fun things I can do in the name of
Armchair Genealogy.
See you next month.
Click on the author's byline for bio and list of other works published by Pencil Stubs Online.
This issue appears in the ezine at www.pencilstubs.com and also in the
blog www.pencilstubs.net with the capability of adding comments at the
latter.
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