DNAeXplained Genetic Genealogy | Discovering Your Ancestors One Gene at a Time

Time 2021-08-31 12:18:57

Web Name: DNAeXplained Genetic Genealogy | Discovering Your Ancestors One Gene at a Time

WebSite: http://dna-explained.com

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Discovering,Your,Genealogy,

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Before we evaluate matches at each of the four major vendors, FamilyTreeDNA, MyHeritage, Ancestry and 23andMe, let’s discuss what a DNA match is, what it means, and what it does NOT mean.A Match to Another PersonEach of the four major vendors, but not some other vendors, provide matches to you and other individuals in their database.This example from FamilyTreeDNA shows my mother s match list listing me as her closest match, along with a kit I uploaded from Ancestry when I was recently updating upload/download article instructions for my readers. You don t need to upload multiple kits to vendors.Every vendor s match list looks different, as is the information they provide. We will cover each vendor s match list individually in future articles in this DNA Beginnings series.Each vendor has different criteria for matching, but in essence, using that vendor’s match criteria – your DNA and the DNA of a person you match are identical on a section of DNA of a vendor-defined length.Each of those vendors identifies the people who match each other and opt-in to matching in one way or another,When you sign on to your account at each vendor, you’ll see a match list. Each of those people on that list match your DNA:At or above the vendor-defined centiMorgan (cM) threshold. You can read more about centiMorgans here.At or above the vendor-defined SNP threshold, meaning the number individual contiguous matching locations.Each vendor has their own thresholds and internal algorithms that define matches. For example, a match of 8 cM with 1500 SNPs refers to both the length of the match (cM) and the density of locations within that segment of DNA that match between two people. Only matches above each vendor s threshold appear on your match list.Matches smaller than or beneath those vendor thresholds are considered less likely to be valid matches, so are excluded and do not appear on your match list.Imputation Affects MatchingDifferent vendors test their customers’ DNA on different DNA chips:Different chips test a different amount of DNA, but generally roughly 700,000 SNP locationsThat 700K locations of DNA can be in different locations in your genomeIn other words, just because two vendors both test 700,000 locations doesn t mean they test the same 700,000 locations.Even the same vendor will, over time, implement different DNA testing chips or modify the SNP locations tested on the same chip.These different chips, chip versions and SNP locations are not fully compatible with each other, so the vendors use a technique known as imputation to level the playing field between non-identical files.This is particularly relevant for vendors that accept uploads from other vendors.In this example, we have 3 vendors and 10 different SNPs, or DNA locations.Vendor 1, on their first Version 1 chip, tested locations 1-8.Vendor 1, on their second V2 chip, tested locations 3-10.Therefore only 6 locations, 3-8, were “common” between those two different chips used by the same vendor.Vendor 2, on yet a different DNA testing chip version (V3) tested locations 1-4 and 7-10.Vendor 3 on chip version V4 tested locations 2-5, 7, 8 and 10.There are only 4 locations out of 10 tested by all the vendors chips.If the vendor’s match criteria is that 10 locations in a row must match, then none of these people will match each other.Sometimes differences occur because of chip differences, and sometimes a difference occurs because a location doesn’t read well for some reason.In order to compensate for the differences in DNA locations tested/reported, a technique called imputation is widely used.Imputation uses scientific probability techniques to fill in the blanks based on DNA that typically neighbors or “travels with” the nucleotides or DNA values, (T, A, C or G), found in the customer being tested.Imputation allows all of those blanks to be filled in for all customers for each of those 10 locations, assuming the missing DNA is close to tested DNA locations.It s thanks to imputation that customers can download their raw DNA files from one vendor and upload to another for matching, even though the vendors don’t use the same exact chip.Sometimes imputation is incorrect. Matching can be affected in both directions, meaning that some people will be on each other’s match lists who actually don’t match on a particular segment. Others would actually match if all of those locations were tested.The highest quality matches are between people who tested at the same vendor, on the same chip or at two different vendors who use exactly the same chip. However, that’s often not possible and isn t within the control of the customer.False Positive MatchesThis translates to, You re a match but not really and is a headache for genealogists.False positive matches show as a match between two people on their match lists, but they aren’t actually valid matches for genealogy.A false positive match could occur as a result of imputation, of course.A false positive match could also occur because the two people match because part of the DNA of their mother and part of the DNA of their father at those locations just happens to combine to appear as a match.For purposes of these examples, presume that each of these matches exceeds the vendor’s match criteria so would be shown on your match list.In our example, Person 1 and Person 2 match at all 10 locations, so they would appear on each other’s match lists.However, if we could see the DNA of Person 2’s parents, we would see that Person 2 DOES match Person 1, but is NOT a valid match. Person 3 inherited the first 5 DNA locations from their mother and the second 5 DNA locations from their father.While Person 2 technically is a match to Person 1, they aren’t a legitimate match because the segment of DNA that matches does not descend from the same parent. This means that the DNA did not descend in one piece from ONE ancestor, but clearly descended in pieces from two ancestors – one maternal and one paternal.Therefore a technical match that is not a genealogical match because the DNA is inherited in part from both parents is known as a false positive and is said to be Identical by Chance, or IBC. You can read about IBC matches here.False Negative MatchesA false negative match is just the opposite. False negatives occur when two people are NOT reported on each other’s match lists when they actually would match if all of the DNA at the various required locations were tested, read, and reported accurately. In other words, if imputation were not necessary.False negatives can be caused by imputation not working as accurately as we would hope. Imputation is a probability tool, and it s not perfect.False negatives can also be caused by differing match thresholds at different vendors.For example, if one vendor reports matches at 6 cM and above, and a second vendor reports matches at 8 cM and above, the same two people who match at 7 cM will match at the first vendor, but not at the second.The only way you would ever know about a false negative match, because they aren’t reported, is if you simply happen to match at a vendor who allows smaller thresholds.Also, keep in mind that each vendor creates their own imputations algorithms, so two different vendors using imputation on the same file may produce different results.Determining Valid MatchesSo, how might you determine which matches are actually valid matches?That’s a great question.There are useful “hints:”If your parents have tested, a valid match will match one of your parents on that same segment of DNA. If your match does NOT match one of your parents, it’s a false positive match and invalid for genealogy.If only one of your parents has tested, and your match does NOT match the tested parent, you can’t presume that person automatically matches your other, non-tested parent. That match could match your non-tested parent, or could be IBC.If neither of your parents have tested, check to see if your match also matches close relatives who have tested, but not your descendants. For example, if a match also matches your aunt or uncle, or first cousins, that increases the probability that the match is probably valid.The larger the match, the more likely it is to be a valid match. For example, matches in the 6-7 cM level are IBC about half the time. By the time you’re evaluating matches at the 20 cM level for a single segment, they are accurate almost all the time.Keep in mind that each matching segment must be confirmed separately, and not every vendor shares the locations of the segments that match.So What Is a Match?A match is a person who is found on your match list at one of the major vendors.A match at one vendor may not be on your match list if you both have DNA at another common vendor due to various reasons including the vendor’s match criteria, imputation, or file compatibility issues.A match may be false positive, or IBC which means that person is not an accurate match for genealogy. This is especially true for smaller segment matches.A false positive match can occur because of erroneous reads, imputation, or because your match is identical by chance.The larger a matching segment of DNA, the more likely it is to be an accurate match meaning you and your match share a common ancestor.The best way to tell if your match is valid is to compare your match to both of your parents as well.A match is not a guarantee that you share a common ancestor unless you are matching to close relatives. You won’t match a close relative if the match is not valid.What About You?What is your plan to verify that your matches are valid?Have your parents tested their DNA? Either of both parents?If so, ask for your parents to upload their DNA with you to each vendor where you upload your own results.At each vendor, you’ll have different matches. That s exactly why we fish in multiple ponds.I always work with my closest matches first, because I m the most likely to be able to easily identify our common ancestor.Locate your closest known relatives from both your mother’s side and your father’s side at each vendor. These people will be extremely helpful for our next article about shared matches._____________________________________________________________DisclosureI receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.Thank you so much.DNA Purchases and Free TransfersFamilyTreeDNA– Y, mitochondrial and autosomal DNA testingMyHeritage DNA– Autosomal DNA testMyHeritage FREE DNA file upload– Transfer your results from other vendors freeAncestryDNA– Autosomal DNA test23andMe Ancestry– Autosomal DNA only, no Health23andMe Ancestry Plus HealthGenealogy Products and ServicesMyHeritage FREE Tree Builder– Genealogy software for your computerMyHeritage Subscription with Free TrialLegacy Family Tree Webinars– Genealogy and DNA classes, subscription-based, some freeLegacy Family Tree Software– Genealogy software for your computerCharting Companion– Charts and Reports to use with your genealogy software or FamilySearchRootsMagic Software– Genealogy software for your computerNewspapers.com – Search newspapers for your ancestorsBooksGenealogical.com– Lots of wonderful genealogy research booksGenealogy ResearchLegacy Tree Genealogists– Professional genealogy researchShare this:PrintTweetEmailLike this:Like Loading... The final goodbye might not be what you think it is, or when. It certainly wasn t what I expected.I thought the final goodbye was when I buried my loved one. Or maybe the final goodbye was the goodbye just before they died when I was saying farewell, in person, for the last time. At least in this realm.Of course, we might not know when we talk to them the last time that it is indeed the final time. That depends on how, when and where they pass over to the other side.It DependsMy biological father died unexpectedly when I was a child. I had no concept of a ”final goodbye” at that age. I presumed he would live forever.I didn’t get to attend his funeral either – so there was no closure at all until I was an adult. In other words, there was no final goodbye other than the last time I saw him which I thought was a “normal” goodbye. Maybe we are all better off that way.Final, when we do know, just seems so…well…final. So much left unsaid – so many feelings we just can’t put into the right words. Feeling the need to say everything we can think of that maybe we should have already said. After all, we know we re not going to get another chance.Sometimes We KnowI definitely knew the last time I saw my older brother, John, that it was the last time. He was suffering from end-stage cancer. He, however, had not accepted that he was approaching death – so for him it was definitely NOT the final goodbye. And because he was still fighting, I couldn’t exactly say goodbye either. I certainly wasn’t going to steal his hope, but I knew nonetheless.My brother, Dave, died just a few months before John. That goodbye was torture. We BOTH knew – and our time together had been so short. We had only found each other as adults and had grown extremely close only to be ripped apart by death.I wanted that discussion to be anything BUT goodbye – yet there we were. He was fighting a losing battle and knew it. We spoke words of gentle love one final time. I assured him that I would see to it that he did not suffer. Trust me, you did not want to be the people who tried to stand in the way of that promise.The Grim Reaper Knows No JusticeMy brave sister, Edna, had survived breast cancer, complete with a double mastectomy and multiple rounds of debilitating chemo. We thought she was finally in the clear and then the sucker punch happened.A heart attack followed by her death about 24 hours later. Edna and I had never said “goodbye” but she was no fool and realized as she endured her cancer therapy that chances weren’t good that she would survive. So while we tiptoed gingerly around the topic, we both knew what was going on.Finally, finally, ever so tenuously we celebrated reports that Edna was cancer-free. We both began to breathe again. Edna and her husband decided to move to the mountains. Their life was back on track, or so we thought.Edna was a realist.Edna had just visited the doctor for a checkup again when she came home and insisted that they needed a vacation. Not later – now. Edna knew something she wasn’t sharing with the rest of us.In a small Arizona mountain town, a few days later, Edna had a heart attack. Cancer is known to cause blood clots.She died the next morning.I never made it to Arizona in time to say goodbye, yet I knew when she passed. And I mean exactly when. I was on the phone with the nurse, because I knew something was very wrong. Then she coded. I literally sat there listening to the hubbub at the nurse s station as they tried to revive her.I knew she was gone.While Edna and I left life unlived, we hadn’t left things unsaid.I didn’t want to see Edna suffer from more cancer treatments. When I found out that her cancer had recurred, I knew that Edna s exit was timely and exactly what she would have wanted.Laughter as the Last Memory The last memory of my mother before her stroke was laughing.I called Mom often as I drove home from work (hands free, with headset.) That spring day, I had stopped in the road to shepherd a mother goose and her goslings out of the road.I quickly told Mom I was stopping and why. She admonished me to be careful and said she knew I would rescue the vulnerable and helpless, no matter what. She heard me “shooing” them because I left the cell phone laying on the seat of the car. I also realized later that if something “bad” had happened, she would have heard that too.But the “bad” thing didn’t happen to me – it happened to her.The next morning I received a call from my sister-in-law, Karen, that Mom had fallen. In reality, Mom fell because she had experienced a stroke, but we didn’t know that yet. Karen stopped to check on Mom and found her on the floor.That’s the call no one ever wants to receive. I left work immediately, quickly packed a bag, and left for the hospital.Hours and hundreds of miles later, Mom could still squeeze my hand, slightly, I think. I realized when she opened her eyes reflexively that she was blind. She couldn’t speak nor could she move. Then, Mom lapsed into a deeper coma. Two miserable weeks later, she FINALLY transitioned. So yes, I got to say many words of goodbye, but I doubt she heard them – at least not with her earthly ears. And if she did, her brain probably couldn’t process them.Looking back, I’m so incredibly grateful that our last communication before that fateful call was us laughing at the goose escapade.A Loving TransitionMy wonderful step-father, Dad, knew he was ready and wanted to go on. We both knew he was leaving soon, a result of worsening chronic disease.At that time, my life was a total MESS, in all caps, with my (former) husband having experienced a massive, debilitating stroke at age 47. Needless to say, I found myself in a position as complete bread-winner with extreme medical bills following his 6-month hospital stay, caregiver to a paralyzed man with neurological deficits, and a parent with two children who were suffering terribly in their own right. I was only able to get away one time for a few hours to visit Dad. There was no help on my end and we lived 6 hours apart.Dad smiled broadly when I entered the hospital room. As ill as he was, love and joy radiated from his face when he saw me. He had a tracheostomy and could talk, at least a little. We both knew time was short.We shared with each other how lucky we both were to have found each other as family, and how much we loved each other. Dad has never left me, even though he left this earth.HorrorHis son, Gary, my step-brother, died unexpectedly in very difficult circumstances the day after Thanksgiving six years after Dad passed away.His death was so horrible that I’m not sharing the details with you. The only thing worse than getting that call” at 5 in the morning is for “that call” to be “that kind” of death.My step-brother’s death was entirely unexpected and there were no goodbyes at all other than standing in shock, graveside, as something containing the words “ashes to ashes, dust to dust,” was read. I have blocked much of that week from my mind.As much as I thought these were all final goodbyes, they really weren’t.The Final Resting PlaceOf those people I just mentioned, three, my Mom, step-Dad and step-brother are all buried within sight of each other in the quaint country cemetery down the road a few miles from the farm. I attended all of their funerals and said goodbye, sobbing, sitting on white folding chairs under a make-shift tent in the cemetery.There is no comfort in funerals for me.I said goodbye to John graveside as we buried him in a cemetery near where he lived, just a week or so after we didn’t say goodbye in his room at “rehab” that was really hospice.My biological Dad is buried near the house in Dunkirk, Indiana where he lived with my step-mother. The process of filling in the blanks in his life, setting his gravestone and finally, just 4 years ago, visiting his grave accompanied by a supportive friend provided the closure I had never achieved previously.One stiflingly hot summer June day in 1990, I stood by my sister, Edna’s grave at her service and tried to read a poem. It took three of us, me plus two of her grandchildren to get all the way through that reading. We would read until we couldn t anymore, then pass it to the person beside us.The poem, A Little Step Away (by O. J. Hanson) was found in Edna s Bible and she had read it at her son-in-law s funeral a few years before.I found some modicum of comfort in the closing stanza:It cannot be, for they live onA little step away.The soul, in everlasting life,Has found a better day.Today, Edna s granddaughter lives across the road and other family members are close by, so I know she’s not alone.That goodbye seemed so unfair. It was a cruel joke for her to suffer so, believe she was cancer-free, and then be gone so soon.I said goodbye to my wonderful brother Dave when the preacher didn’t show up at his funeral and I unexpectedly gave an impromptu eulogy. I still laugh at that and Dave would have too.Dave was cremated and never buried, so there is no “place” to visit to commune with him. There may have been ashes to ashes but those ashes are still transitory someplace. I just talk to him from time to time.Dave took this photo through his semi-truck window someplace on the road on one of his last runs. To me, this is where Dave is, aside from watching over me.For my daughter, Rachel, who was born prematurely, died a few hours after birth and was “disposed of” by hospital personnel, there will never be closure. As part of me, she accompanies me wherever I go. Like Dave, there is no “place” to say goodbye or visit – so she just travels along in my heart.CemeteriesWhile funerals don’t bring me comfort, the cemetery is at least a place to go to reflect, honor, and sometimes to talk to our departed family members.It’s a place to visit after that “final” goodbye. Even though we know the essence of who they “were” isn’t “there” anymore – we go anyway. For them. For us. To grieve. To honor their life. To take flowers. To perform whatever loving maintenance we can do for them. Pull a weed or two. Plant something. Anything.To tell them we are so sorry they aren’t here with us any longer in the flesh and that we had to say that goodbye in whatever form it manifested.But those those were not the final goodbyes – even though I thought they were at the time. In fact, I thought they were right up until this summer.The TombstoneThere is ying and yang to everything in life.A grave and tombstone marks the location of the last remains of our loved ones. We can stand or sit on the grave and be just 5 or 6 vertical feet away. We purchase a marker in tribute so our family members will never be forgotten. Our last “thing” to do for them – something intransient that remains with them forever, or at least until the ravages of time erode their names on those stones.Of course, that’s just for graves in cultures where gravesites are not reused. For those whose graves are later shared with another, who are cremated or never buried for some reason, we have to adjust our thinking to something else. Find another way to memorialize and honor both their lives and absence. There won’t be any place for their descendants, if they have any, to search for, find and visit in another hundred years, or two. There is no tombstone which gives us at least the illusion of permanence.Of course, sooner than later, their tombstone, or lack thereof, will be irrelevant to us. We’ll have joined them. Maybe it’s not just the funeral that’s for the living, but the grave too.The Final, Really, Really Final GoodbyeI hadn’t been back to Mom and Dad’s graves in two or three years. They aren’t exactly on the way to anyplace. The last time I visited, I told them I didn’t know when I’d be back again.Clearly, that was with the expectation that I would return. I did, a few weeks ago, but this time was very different.This time is the final, really, really final goodbye.I know I’m likely never returning. I know better than to say “never” in the absolute sense. Why would I never return to my parents and brother’s graves?One of three things:My own time is limitedI’m unable to return for some reasonI’m moving even further away with nothing to bring me backI’m fine. It’s number 3.I’m excited for this new chapter to begin, but I never, ever expected the emotional response of that the final really, really final goodbye.That Last VisitI needed to make a final trip to Indiana and decided to take Mom and Dad a special bouquet of flowers this time. Normally, I purchase bouquets of live flowers, but I wanted something to last a little longer – even though I know they will be thrown away a few months from now.Two bouquets of silk flowers have lived in my house for years. My favorites. My daughter gave me a hand-made gift a year or so ago that was gifted in a basket. I arranged the silk flowers for my mother in the basket as I didn’t want to leave a glass container in the cemetery.I knew my daughter would want to be included.When Mom was so ill, my daughter took off work, which she could ill-afford at the time and stayed with me at Mom’s side those final incredibly difficult days waiting for Mom to pass. I was extremely grateful and I know Mom, somehow, knew she was there.The day that I went to the cemetery the last time was part of an emotion-filled weekend with multiple goodbyes in different ways.One decades-delayed goodbye was to Robert Vernon Estes at the Indiana War Memorial POW/MIA ceremony.The second goodbye was gut-wrenching with a close family member in a situation I can’t discuss.The third was this final visit to the cemetery.By the end of the weekend, I felt I had been put through the emotional shredder.Back Roads and Corn FieldsIt had been three years since I had returned to Galveston, a tiny crossroads village with a 4-way flasher on the way to exactly no place.I made my way across the back roads of Indiana and realized that the corn is as tall as me, or taller. A tractor was mowing hay. Kids were playing in the sprinklers in yards. It smelled like summer.An old gas station was frozen in time at an even tinier intersection with maybe 10 houses.Nothing much had changed. The hazy mid-summer Hoosier countryside is timeless.While the real estate market in the rest of the country is smoking-hot right now, not so in rural Indiana. For sale signs that have clearly been planted in the front yard for months based on the unmowed grass around the signs and the washed-out words tell the tale that no one wants to move there.The center lines of the small roads are worn off by years of local traffic. Many intersections have crosses and flowers strapped to the posts of stop signs – signaling a fatal accident took place there.I remembered my own accident at one of those crossroads when another driver ran the stop sign. The corn was too high to see them approaching and I only caught the briefest glimpse of them before that horrible crash some 40 years ago.On this particularly hot summer day, I was glad to finally arrive at the cemetery – as a visitor.The cemetery where Mom rests used to be a cornfield and is two or three blocks long and maybe half as wide. Those are city blocks, not country blocks

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