Saturday, April 28, 2018
Explaining DNA Tests of 5th cousins of FTDNA and generations ago of GedMatch
Nadene Goldfoot
My DNA tests with Family Tree DNA have come up with many 5th cousins. This means I have cousins that share one of their 32 gggggrandmothers or gggggrandfathers with me. That's going back very far, 6 generations.
What is a generation? 25 years is considered a generation. We had 2 ancestors, our mother and our father for starters. We receive 50% of our DNA from our mother and 50% from our father.
Our 1st cousins share their grandparents with us. It used to be that a couple could have easily had 10 children, even more. Today that doesn't happen very often. There are a lot of single children without any siblings. Their parents may have had siblings who had children, so they do have 1st cousins.
GedMatch shows relationship measured by generations. 6 generations ago, we had 64 ancestors. 32 were females and 32 were males. They were our gggggrandparents. They were born about 150 years ago or to the year 1868, being this is 2018. We received 1.5625% of our DNA from each one.
I've never seen this, but if GedMatch showed that someone was related to us 10 generations ago, they would be our 9th cousins. By then we would have had 1,024 ancestors. 512 of them would be males and 512 would be females. They would be our gggggggggrandparents. They would have been born about 250 years ago or born in 1768. We would have inherited 0.09765625% of our DNA from each one.
Family Tree DNA will say 5th cousin Remote cousin if the match shows only a certain amount of cMs and a certain amount of segments that equal being a 5th cousin, and even less showing the remote relationship. They do not go past the 5th cousin remark. One new 5th cousin I have recently found shares 86.76281
The 25 years equaling one generation comes about from a woman's ability to have a child. She has child-bearing capability from marriage at age 18 to the time of her menses which would be about age 45. She can be 18 and a mother. 25 would be her average age, so a generation can certainly vary depending on when mothers and grandmothers were born and how old they were when giving birth.
The DNA company has a tool to figure this out according to how many cMs are shared versus how many segments they come from. That's how they came up with 5.6 generations instead of 7 generations. This means the connection with this distant cousin could be 140 years ago to 175 years ago. Our common ancestor could have been born anywhere from 1878 to further back in 1843. That's a span of 35 years, another whole generation.
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| A first cousin overnight reunion. In this picture is my brother and his wife, a cousin from my father's side, myself, and 3 siblings that are our maternal first cousins with one spouse. It was taken in July of 2017. There is one cousin here who tested. On GedMatch we share 945.5cMs over 37 segments. The largest segment was 76.3cMs. This showed we had Estimated number of generations to MRCA = 2.0 (Most recent common ancestor). 2 generations ago went back to our grandparents. |
My DNA tests with Family Tree DNA have come up with many 5th cousins. This means I have cousins that share one of their 32 gggggrandmothers or gggggrandfathers with me. That's going back very far, 6 generations.
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| My father and myself |
Our 1st cousins share their grandparents with us. It used to be that a couple could have easily had 10 children, even more. Today that doesn't happen very often. There are a lot of single children without any siblings. Their parents may have had siblings who had children, so they do have 1st cousins.
GedMatch shows relationship measured by generations. 6 generations ago, we had 64 ancestors. 32 were females and 32 were males. They were our gggggrandparents. They were born about 150 years ago or to the year 1868, being this is 2018. We received 1.5625% of our DNA from each one.
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| Going way back, Major Aaron Robinson is in this picture. He was born in 1768 in Bennington, Vermont. He could be my 1st cousin 6 X removed, or 6 generations distant (a 5th cousin). This is figured from Family Tree Maker, my software program. You can find it online today. | .. |
Family Tree DNA will say 5th cousin Remote cousin if the match shows only a certain amount of cMs and a certain amount of segments that equal being a 5th cousin, and even less showing the remote relationship. They do not go past the 5th cousin remark. One new 5th cousin I have recently found shares 86.76281
25 with me. This is from FTDNA.
Her granddaughter shares 29.28478
6 with me. It's less, being the 6th cousin. That's a distance of 7 generations where we are sharing 64 females and 64 males. Each of our ggggggrandparents are giving us 0.390625% of our DNA. However, the generations shown that are distant on GedMatch are only 5.6 generations instead of my 7 generations.
The 25 years equaling one generation comes about from a woman's ability to have a child. She has child-bearing capability from marriage at age 18 to the time of her menses which would be about age 45. She can be 18 and a mother. 25 would be her average age, so a generation can certainly vary depending on when mothers and grandmothers were born and how old they were when giving birth.
The DNA company has a tool to figure this out according to how many cMs are shared versus how many segments they come from. That's how they came up with 5.6 generations instead of 7 generations. This means the connection with this distant cousin could be 140 years ago to 175 years ago. Our common ancestor could have been born anywhere from 1878 to further back in 1843. That's a span of 35 years, another whole generation.
Resource: Family Tree DNA, GedMatch.com
Chart; unknown origin, but online
Chart; unknown origin, but online
Labels: Family Tree DNA, GedMatch, genealogy, generations, MCRA
