#visual phasing

[dnagenealogy]

Can a 6 cM connection be meaningful?

When it comes to small DNA segments, we’ve heard the “glass half empty” version of the story many times. Here’s the other side of that story.

Submitted for your consideration: A pair of third cousins twice removed and their 6 cM connection…

According to AncestryDNA, Bryan Smith and his cousin, K, share 6 cM of DNA across 1 segment. And according to Ancestry’s ThruLines, Bryan and Cousin K share a pair of third great grandparents, Reuben Willis Smith and his wife Mary Connell.

The cM value is certainly consistent with the identified relationship but did Bryan and Cousin K inherit their shared DNA from the Smith ancestry as shown? Is the 6 cM segment even valid or could it be an artifact of an imperfect DNA matching algorithm?

Let’s start with an easy evaluation: the shared match list.

Among Bryan and K’s list of shared matches at AncestryDNA:

HG, a descendant of Reuben and Mary’s son, Charles Thomas Smith (HG shares 57 cM with Bryan)

RR, a descendant of Reuben and Mary’s daughter, Fannie Janes Smith (RR shares 47 cM with Bryan and 38 cM with K)

IG, another descendant of Reuben and Mary’s son, Charles Thomas Smith (IG shares 47 cM with Bryan and 71 cM with K)

And at least three other descendants of Reuben and Mary are on the shared match list.

So we’re off to a promising start. In addition to the fact that Bryan and K share DNA and a paper trail leading to Ruben and Mary, this group of matches gives us more evidence suggesting that Bryan and K might be related as suspected.

But what about that 6 cM segment shared by Bryan and K? Is it valid? Did it come from the shared Smith ancestors or did it originate elsewhere?

To get the most comprehensive help in answering these questions, we turn to GEDmatch. As indicated in the ThruLine image above, both Bryan and his father are related to DNA Cousin K through their Smith line. And because K is on GEDmatch, we can see that Bryan and his father both share DNA with K on a specific portion of Chromosome 12:

Further investigation reveals that two other descendants of Reuben and Mary, Cousins I and G, share DNA with Bryan and his father on Chromosome 12 in roughly the same location. In fact, all of the matches in question match each other on Chromosome 12:

This is what we call a Triangulation Group. It brings the possible genetic connections into sharper focus.

The common segment shared by all of the members of this Triangulation Group indicates that they all share a common ancestor. And we’ve already identified shared ancestry through the Smith line. Cousins I and G are first cousins once removed and they are descendants of Reuben and Mary’s son Charles Thomas Smith...

A review of the pedigrees of the matches in question reveals no lines of shared ancestry other than the known shared Smith line. This investigation is summarized briefly in the table below, listing 2nd great grandparent surnames and shared ancestors (blue for paternal names and surnames, light red for maternal names and surnames):

Although we cannot say with perfect certainty that there is no additional common ancestry that conceivably could account for the shared segment of DNA on Chromosome 12, the known evidence doesn’t leave room for much doubt.

For completeness, here’s a chart summarizing the amount of DNA shared by the relatives in question:

And cluster analysis for Cousin G yields a cluster with eight descendants of Reuben Willis Smith, including Bryan Smith and Cousin K:

Not everyone will feel the need to go this far to investigate a 6 cM connection. But this post provides examples of ways to investigate the validity of an ordinary small segment and to determine whether the shared DNA legitimately belongs with the presumed paper trail source of the DNA.

Discussion

Skepticism regarding small segments of shared DNA is appropriate. In comparison to larger shared segments, such segments are more likely to be IBS (false).  Additionally, even when small segments can be shown to be reliable, we have to grapple with the fact that small segments can be too old to fall within the reach of reliable historical documentation. 

With the exponential growth of the DNA matching databases, the impetus to explore distant matches waned. Reluctance to do the strenuous work involved in using small segments grew. With access to strong genetic connections leading back to target ancestors, why bother with low cM connections?

The sentiment is understandable!

On the other hand, I believe that excessive skepticism has impeded progress in genetic genealogy.  As databases have grown, our opportunities for research have multiplied and our research techniques have improved. But at the same time, goalposts for small segment success have been moved to poorly-defined and very unreasonable points. 

[From the skeptics: Your success with a small segment doesn’t count if you find a larger segment in a relative! I don’t want to hear about triangulation! Visual phasing is not allowed!]

If we applied such arbitrary restrictions to all areas of genealogy, we’d struggle to get our work done!

Even with our luxuriously large DNA databases, distant genetic connections are the only connections available in some areas of investigation (or to people who hail from less heavily-tested populations). Defeatist refusal to accept low cM matches as evidence in genetic genealogy needlessly limits our potential. 

Don’t get me wrong, I’m fully in favor of scholarly rigor. But let’s not allow skepticism to pave the way for denialism! 

When distant genetic connections are found to be of dubious quality, they should be set aside. But shared segments should not be judged on the basis of size alone. Even the most fervent opponents of small-segment research will admit that small segments are often valid (IBD). And while these opponents frequently cite IBD/IBS percentages, they ironically fail to see that our ability to find these percentages points directly to a practical method for sorting distant matches on an individual basis. 

We are privileged to have access to enormous databases of incredibly valuable genetic information. More than a statistical hiccup that can lead us serendipitously to more reliable information, small DNA segments are  messages we carry with us every day, testifying to our connections with our ancestors. Genetic information, even in small amounts, can be just as valuable as any other form of information. We should be good stewards of that information and we should invest good faith effort in understanding how our distant matches can inform us about our rich ancestral history. 

I’ll close with this analogy for small segments: 

You want some refreshing water but the glass is only half-full. Drink it or toss it out?

Posted with Bryan Smith’s permission. 17 May 2023

[bruhstation]

“Do you know why humans often say the phrase "It’s a small world"?"

From the studio that brought you Love Train, Senja/Bruhstation presents:

🚧🚂 CASA TIDMOUTH ‘85: SUMMER PHANTASM OF THE RAILWAY 🚂🚧

Your name is Edward. Two years ago, you were thrown into the island of Sodor without your memories or your sense of self intact. The years working as a driver for the NWR 2 have shaped you into a highly reliable, amicable, and strong man of perseverance. The only thing that remains of your long forgotten past is your insatiable thirst for knowledge, and the only thing that you have obtained is a set of golden eyes that you’ve been keeping a secret from your two friends.

When terror lurks among the rails, you are thrust into a journey to send the wraith that’s been using people’s bodies for sustenance back to where he belongs, knowing full well that you might not be equipped to confront what lies beyond the fog.

Unfortunately, the people you’ve been shielding from the horrors only known to you will be caught in the crossfire. Still, you’ll do anything to keep the island safe, no?

This game features:

Fully voiced cast

Original soundtrack

Six different endings

30+ hours of gameplay

Gallery of CGs and character files

Secrets... perchance?

With the subject matter that this story brings, this visual novel is not recommended to:

Those who are sensitive to sudden sounds, flashes of light, or intense imagery

Those with health conditions such as epilepsy or heart problems

Those who are sensitive to portrayals of possession, dereality, bullying, and ableism

Those who actively seek momentary happiness in an otherwise bleak world 

Those who take pleasure in destroying themselves and their loved ones

Those who are elitist about a specific season or media of a certain talking train franchise 

Wishlist on steam | itch.io link

Development log:

I’m sorry.

[wyervan]

I'm curious how many piercings does Moon (slasher au) have?

@mother-of-horror i was thinking of some of your recent work and talk of religious imagery while painting tonight :3c

Just the one lobe pair on Sun! He likes wearing his big gold hoops or gemstone studs.

(Also Sun in a half-bun to satisfy the people in my inbox asking to see him with a different hairstyle)

Moon has two lobe and two helix piercings on his right, and two lobe and ONE helix on his left. Soon after he got it pierced, the second helix on that side got infected and he had to take it out to let it heal. He prefers the look of small hoops and metal studs.

I got carried away with these paintings but i wanted to experiment with some abstracted shapes and textures.

[fluffytheocelot]

Reflecty werewolf eyes :3

Also the next chapter has fully escaped. Like a certain red werewolf grabbed it and is now running away with it. It is much closer to being done but the total word count is like 17k 💀 I’m very excited for it tho :D

[fatedroses]

More than just the Demon.

[cronchybuffalo]

TW: Excess blood and cartoony/unrealistic gore under, I better not getting shadowban for this or Ima del and privatteer linked

[thetypewriterdaily]

💌gentle reminder: you’re still you in all the phases you go through. you don’t have to be whole or perfect to be worthy. you’re enough just as you are 🌕🌖🌘🌑 (swipe for cute moon animation🥰)

[eightyuh]

Was working on updating my banner but forgot I was gonna phase out meat being featured on my graphics — thought this still looked cute tho 🥩🍗🥓🍖🦇

[slutpoppers]

[beatcroc]

today im mad about omega being TWO ENTIRE FEET shorter than the predecessor e-100s

gamma on the left, omega on the right. imagine being a pissed off killer robot but youre not even 5 feet tall. and your kindly self-sacrificial nerd of a cousin got to be 7 whole feet.

like do you understand what that looks like.

this is absurd. that's stupid. you'd think it's bad scaling on my part because gamma has no official art where he's standing mostly straight and at an easily-comparable angle, but no it's consistent with sigma's scrapnik ref, these guys are literally just fucking massive for no reason

the sa1 e-series guys aren't even proportioned like 7' guys they look like they should be like 5'. look at omegas tiny fucking head. omega literally has the build and proportions to be a proper giant killer robot but hes fucking 4' 11'' because he has to play nice with the funny little furries and thus can only be a specific magnitude larger and more imposing than them. *i* should not be nearly a whole foot taller than omega. i could lean condescendingly on his tiny fucking head. maybe he would have been more willing to give eggman another chance if they hadn't shrunk all his rage into a 4-foot frame. im choosing to believe also this is why he's a solid 50% heavier than gamma as well. dude is compact. dude is DENSE. and he is so very full of guns and rage. i dont know what the doctor expected

[dnagenealogy]

We need a chromosome browser at AncestryDNA!

Andy makes some incredibly strong points in this video and he makes them very well. It's a huge step in the right direction. I hope he's willing to go further with it. He has one foot on "a chromosome browser isn't needed most of the time…it is not used for the vast majority of your genealogy questions" and the other foot on "chromosome browsers are essential…we need a chromosome browser." I know it's dangerous to take a stand that will rub people at Ancestry the wrong way but if we're going to get a chromosome browser at AncestryDNA, we can't vacillate.

[chaoscouncilcreaturecorner]

Moon Stimboard

[eyes1nthewoods]

wait actually. how did that meeting lann's mom go for maercy sjsbshnsj

she completely misunderstood what ria was asking

[clownboymcchucklefuck]

What do we think of this song being a Zachary vibe

[gallusrostromegalus]

If anyone wondered where I've been: I've been dog sitting at my parents house and am closing in on finishing the outline for AEIWAM so I can start posting.

Today's highlight was "I guess what I'm really asking is: what's everyone going to therapy for, and what does the solution to that particular issue look like if physicalized into a weapon or tool?"

[ksore2]

I remembered that I used to be a gachatuber,so I made Ren and MC in Gacha Life 2 :3

Tell me what do you think ? :>

Maybe I will make another character,who knows XD