A Basic Explanation of Genetic DNA as it Applies to Genealogy |
| December 3, 2010:
In my continued effort to understand the principles of genetic DNA as it applies to genealogy, I asked Suzanne Sears (Co-Administrator of the Cyr Surname DNA Group Project, which I Administer), to provide me a _basic_ explanation of the process, as it pertains to Pierre Sire (my first ancestor) and my own DNA testing. In part, my message to Suzanne stated: “Suzanne, I still have difficulty getting my head around how Pierre Sire can be traced, when we don’t (obviously) have HIS DNA… and never will. Can you give me a _simple_ [actually, _very simple_] 🙂 explanation!” Here is Suzanne’s reply: We DO have Pierre’s DNA………….You and Peter (another tested member of the Cyr Surname DNA Group)……….an exact copy……….that’s why you two are nearly perfect copies of each other……. and you both descend from Pierre. It works like this…………. Lets assume Pierre is one of 5 original men on the planet………..for now. DNA is two spindles of thread……….. One male Those two spindles are the blueprints for making a human being. The two spindles twirl around each other………… But if you break them apart: you will get one female spindle ——————- So when Pierre took a wife……….. to make a new human being……… His DNA spindle broke apart…………into a male and a female portion…….. The female portion was scrapped………only the male portion would go forward to be used for the baby His wife: same thing: her DNA broke apart…………. her female DNA But now the male part is scrapped and only the female part goes ahead…….. ———- So we take the male thread from Pierre and bingo: you have Jean Baptiste………..and Jean Francois, and Guillaume Each one of these men carries that first thread from Pierre……………in a near perfect copy…….the odd mutation. ———— And every single male from then onwards: always is using that same first thread of Pierre So you today: are a mix of Pierres first thread and whomever your mother was……… But Pierres original thread is in you………… and for every male for all time: down the Pierre Sirre lineage: It never never never changes……..not the male DNA…………down the male side…………. The question we dont know is: who did Pierre get his thread from………who was his father……….. ————— 12 markers is a good idea of the basic white cotten thread that was the starting point anciently………… So using your imagination now think back 1,000 years………..and there is a tribe somewhere in Germany of 10 men…… and spread it forward through sons to get to Pierre……………and now you and Peter ————- Pierre lives in you…………..if he was here: even 400years later: your male DNA would be an identical match within just a small variation…… No one else on this planet would match Pierre Sirre better than you and Peter………. Time makes little to no difference ———— Example: they found a cave in Germany with about 3,000 old skeletons: obviously from some kind of war So on whim: they said: lets test people nearby…………..within 30k……….to see who was here back then and who is here now And they found genetic matches!!!! People genetically related to these dead guys from 3,000 years ago: all still living in the same damn place. Thats why DNA is valuable for geography: people really dont move all that much……….despite modern times. Like you expect to find polar bears in the Arctic: but if you find one in the North West Territories: you arent too surprised: but it might be just a few. Well people are pretty much like that too……………a few move: most dont shift far from their ancestral homes. ——- So using Pierres DNA we can without a doubt find where he came from: possibly over to Belgium and Holland……… This is his ancestral home base……….. doesnt mean he lived there in 1644………only that most of his kin folk did. ————- Hope this helps a bit……… There are no unique human beings: each of us is a copy of someone who lived before right back to 250,000 years ago. Of the native women in Canada: they all come from just 5 original women: 250,000 years ago. Each one alive today is a copy of one that lived then. Here’s an easier way to understand what I wrote in the previous email Imagine: A white thread in your left hand: a Male thread Now twist and twirl them together=a new human being ——————- Lets argue it’s a son…………. Now this son gets married and has a baby His threads unravel………..and goes back to being separate threads One white male thread Just like it was when his parents got together and shared their DNA to make him…… His wifes DNA will do the same thing……… she too has her DNA broken down into 2 threads…….. So now we are going to make a new human……… We will take the male thread from this original son (the rest is scrapped: the male dumps his female thread ——————- So now we have: a white thread from the male son and they twist back up to make a new person………… ————————- the key point to remember though is: That white male thread is the same darn white male thread this new father to be He never got new white threads…….. for the next 100,000 years: all the males will reuse that same white male thread: thats why your white male thread is a copy of Pierre……….. and he got it from his Dad and all your sons will have that same white thread… 250,000 years from now: All males that descend from Pierre will still be using that same white thread……. ——————- It just keeps unravelling and then tieing back up as each child is born And thats why we only use Male DNA to do the tracking with………….because its the same white thread since the beginning of time……..with just a very few breakages or mutations along the way ——————— Its only the female DNA that creates variation…….mtDNA………. but we will never know Pierres female DNA thread………because he never had any sisters that we know of……….and he doesnt pass forward female DNA……..only his own male DNA….. The male DNA never never changes…………. It’s a recipe……..that never changes………… ———- So when they do DNA testing: they break the male and female threads apart: and give you the outline of the male thread…… ——————————- The numbers indicate how many…….. so for example: At maker 390=23 It means: in that small space called 390………..there are 23 repeats of a chemical…….. In my DNA at 390= I have 24 repeats of that chemical……… Thats how we know we arent bloodline related………… Because Pierres thread carried 23 repeats The pattern of the thread repeats itself so nearly perfectly each time. ————— so on a tribal level: only persons with 23 repeats at 390 share the same tribal background: the Frankish Germans and I share a tribal background with those humans who had 24: ………the Celts this is how they know that Germans and Celts were not the same race of people……. ————————— When you review basic 12 marker tests for the numbers: it is telling you how many repeats there are at each step along the way 13 23 14 11 Means… Now they can tell you: that people with this exact pattern of repeated numbers: they can track them backwards in time to the biggest concentrations of these patterns ——— Mine is: 13 24 14 10………and they can also tell you where that pattern was back in time……… So while your people were somewhere in Frankish German territory ———- These are called Clusters………and certain patterns of numbers cluster in certain geographies Just like Penguins: who have their own DNA are not found in the Sahara in general……… And Pierres pattern clusters around Holland……some to the left and some to the south and some to the north………. In particular he shares some unique marker repeat sequences yDNA and mtDNA are NOT the same thing: yDNA is the “thread” that passes strictly from male to male for all time…….. Females DON’T have it…….. Humans are made up of 23 pairs of chromosome: = 46 total They are numbered one through 23: from smallest size to largest size The number 23 Chromosome is the one which determines our sex one; whether we are male or female. it tells you nothing about the male lineage [Note from Yvon: Suzanne is the Co-Administrator of my Cyr Family DNA Group Project] |