Friday: 7 July 2006
No, it’s not a new Wes Craven horror movie, although you may think so by the end.
When I was a little kid, I was fascinated by genealogy. Of course in the 1960’s there wasn’t much way for a little kid to research family history and so I put that on the back burner and got into evolutionary biology instead.
My father, on the other hand, has been doing his own research and adding that of others for at least the last ten years. He’s managed to put together a set of files on various family branches that I’ve merged to produce one big file. At present it contains about 1600 individuals. Of course at least 300 of those derive from a connection (that many people have) to the Lincolns (as in Abraham) and once you make a connection like that to a well-researched family line you can add a lot to the database. Except for that branch that produced my father’s mother, there are not many individuals listed that date back further than 1800 or so.
(Parenthetically, Glenn’s mother spent much of the 80’s doing genealogical research into her and Glenn’s father’s families, generally going back much further. She eventually compiled the data into six books, but did not have the time or inclination to get them into a database. I’ve gotten two of the books into the database. I’m about to get going on completing that effort I let lapse a couple of years ago. I have a mild interest in seeing if Glenn and I are related in any way
).
I’ve understood, but can’t confirm, that the terminology “cousins” is not properly used by Americans. Perhaps it’s only used incorrectly by southerners, or maybe it’s my own private misuse. Maybe it’s generally misused everywhere. I’ll go with the “most Americans” assumption here and put the question to you at the end.
The incorrect usage that I grew up with is this - the child of your first cousin is your second cousin. Her child is your third cousin. And so forth.
Wrong. The child of your first cousin is also your first cousin (as are all your first cousin’s descendents) but is removed once by marriage, i.e., is one generation removed from you. It works the same way going backward in time too.
Here’s how it (apparently) works, and it’s actually rather elegant. It even has a sort of a parallel with evolutionary biology terms, but we’ll skip that for today.
You share a group of people through your parents. We call these your siblings, your brothers and sisters, your very closest immediate family.
Broaden things a little. You share a larger group of people through your grandparents on one side or the other, that is, everyone in this group has the same grandparents. Except for your siblings, all these people are your first cousins.
There’s an even larger group that shares with you a common relationship with your great-grandparents. Excepting your siblings and first cousins, these people are properly called your second cousins.
You and your third cousins share a common relationship but only from your second great grandparents, that is, your great-great-grandparents. You probably don’t even know these people.
Then there’s the “removed by marriage” part. Simply count the number of generations between you and the person of interest and that’s how many times you’re removed by marriage.
Here’s an example.
The daughter of my father’s sister is my first cousin, because we share a common grandfather and grandmother on my father’s side. My cousin’s son and daughter are also my first cousins, but once removed by marriage, since they’re one generation away from me, and vice-versa. We still share my grandparents, who are their great-grandparents (but my relationship, which is closer, takes precedence in figuring all this out). If one or the other of those kids has kids, their kids will be my first cousins twice removed by marriage.
Another example:
My father’s mother is a Lincoln. (Hmm, “My Grandma The Car”? No, I mean the surname.) Her 4th-great grandfather, Mordecai Lincoln, was Abraham Lincoln’s 2nd-great grandfather and my 6th-great grandfather. Since Abraham Lincoln and I share his 2nd-great grandfather, we are third cousins, but we’re also four generations apart so we’re third cousins four times removed. An extremely tenuous relationship that a huge number of people can claim, by the way.
(There’s always amusing little twists to be found. Get a load of this: occasionally you run into someone who is not only your second cousin twice removed, for instance, but also your great-grand aunt. Hmmmm.)
Here’s how it works genomically, and I knew you were hoping I’d address this. I hope I got it right.
You share half your DNA with each of your parents and brothers and sisters. If any individuals are half-relations, you knock that share down by 1/2.
You share a quarter of your DNA with each of your four grandparents, as well as with your nieces, nephews, aunts, and uncles. (That brings up another ambiguity of terminology: your mother’s sister is your aunt, of course, but your grandmother’s sister is your *grandaunt*, not your “great aunt”. Your great-grandfather’s sister is your great-grandaunt, and so forth. Uncles work the same way.)
You share 1/8 of your DNA with your first cousins (unremoved by marriage), as well as with your great-grandparents. With each removal, that share goes down by half.
You share 1/16 of your DNA with your second cousins and 2nd-great grandparents, and so on.
I share 1/32 of my DNA with my third cousins, but since Abraham Lincoln is four times removed, the total share is 1/512. Of course that *is* 12 million nucleotides of DNA, but in a genome that has 6 *billion* nucleotides, well, that’s how tenuous that relationship is. And because the relationship is through my grandmother, we don’t even share a Y-chromosome!
Why is this important? I’ve drawn the line, with some possible exceptions, at attending weddings (and buying wedding present for) anyone who shares less than a quarter of my DNA. I got snookered a couple of years ago into attending the wedding of a first *half*-cousin once removed with whom I shared only 1/32 of my DNA, and had never even *met*, and I don’t think the toaster and dishtowels were worth it. Besides which, it took her over a year to write a thank-you, and she was looking at that damn toaster every morning. (It was, though, fun for the shenannigans that those I shared 1/4 or more of my DNA with engaged in.)
So the question is - is this how most people perceive the “cousin terminology” and understand it? Or do they have it the wrong way?
When I was a little kid, I was fascinated by genealogy. Of course in the 1960’s there wasn’t much way for a little kid to research family history and so I put that on the back burner and got into evolutionary biology instead.
My father, on the other hand, has been doing his own research and adding that of others for at least the last ten years. He’s managed to put together a set of files on various family branches that I’ve merged to produce one big file. At present it contains about 1600 individuals. Of course at least 300 of those derive from a connection (that many people have) to the Lincolns (as in Abraham) and once you make a connection like that to a well-researched family line you can add a lot to the database. Except for that branch that produced my father’s mother, there are not many individuals listed that date back further than 1800 or so.
(Parenthetically, Glenn’s mother spent much of the 80’s doing genealogical research into her and Glenn’s father’s families, generally going back much further. She eventually compiled the data into six books, but did not have the time or inclination to get them into a database. I’ve gotten two of the books into the database. I’m about to get going on completing that effort I let lapse a couple of years ago. I have a mild interest in seeing if Glenn and I are related in any way
).I’ve understood, but can’t confirm, that the terminology “cousins” is not properly used by Americans. Perhaps it’s only used incorrectly by southerners, or maybe it’s my own private misuse. Maybe it’s generally misused everywhere. I’ll go with the “most Americans” assumption here and put the question to you at the end.
The incorrect usage that I grew up with is this - the child of your first cousin is your second cousin. Her child is your third cousin. And so forth.
Wrong. The child of your first cousin is also your first cousin (as are all your first cousin’s descendents) but is removed once by marriage, i.e., is one generation removed from you. It works the same way going backward in time too.
Here’s how it (apparently) works, and it’s actually rather elegant. It even has a sort of a parallel with evolutionary biology terms, but we’ll skip that for today.
You share a group of people through your parents. We call these your siblings, your brothers and sisters, your very closest immediate family.
Broaden things a little. You share a larger group of people through your grandparents on one side or the other, that is, everyone in this group has the same grandparents. Except for your siblings, all these people are your first cousins.
There’s an even larger group that shares with you a common relationship with your great-grandparents. Excepting your siblings and first cousins, these people are properly called your second cousins.
You and your third cousins share a common relationship but only from your second great grandparents, that is, your great-great-grandparents. You probably don’t even know these people.
Then there’s the “removed by marriage” part. Simply count the number of generations between you and the person of interest and that’s how many times you’re removed by marriage.
Here’s an example.
The daughter of my father’s sister is my first cousin, because we share a common grandfather and grandmother on my father’s side. My cousin’s son and daughter are also my first cousins, but once removed by marriage, since they’re one generation away from me, and vice-versa. We still share my grandparents, who are their great-grandparents (but my relationship, which is closer, takes precedence in figuring all this out). If one or the other of those kids has kids, their kids will be my first cousins twice removed by marriage.
Another example:
My father’s mother is a Lincoln. (Hmm, “My Grandma The Car”? No, I mean the surname.) Her 4th-great grandfather, Mordecai Lincoln, was Abraham Lincoln’s 2nd-great grandfather and my 6th-great grandfather. Since Abraham Lincoln and I share his 2nd-great grandfather, we are third cousins, but we’re also four generations apart so we’re third cousins four times removed. An extremely tenuous relationship that a huge number of people can claim, by the way.
(There’s always amusing little twists to be found. Get a load of this: occasionally you run into someone who is not only your second cousin twice removed, for instance, but also your great-grand aunt. Hmmmm.)
Here’s how it works genomically, and I knew you were hoping I’d address this. I hope I got it right.
You share half your DNA with each of your parents and brothers and sisters. If any individuals are half-relations, you knock that share down by 1/2.
You share a quarter of your DNA with each of your four grandparents, as well as with your nieces, nephews, aunts, and uncles. (That brings up another ambiguity of terminology: your mother’s sister is your aunt, of course, but your grandmother’s sister is your *grandaunt*, not your “great aunt”. Your great-grandfather’s sister is your great-grandaunt, and so forth. Uncles work the same way.)
You share 1/8 of your DNA with your first cousins (unremoved by marriage), as well as with your great-grandparents. With each removal, that share goes down by half.
You share 1/16 of your DNA with your second cousins and 2nd-great grandparents, and so on.
I share 1/32 of my DNA with my third cousins, but since Abraham Lincoln is four times removed, the total share is 1/512. Of course that *is* 12 million nucleotides of DNA, but in a genome that has 6 *billion* nucleotides, well, that’s how tenuous that relationship is. And because the relationship is through my grandmother, we don’t even share a Y-chromosome!
Why is this important? I’ve drawn the line, with some possible exceptions, at attending weddings (and buying wedding present for) anyone who shares less than a quarter of my DNA. I got snookered a couple of years ago into attending the wedding of a first *half*-cousin once removed with whom I shared only 1/32 of my DNA, and had never even *met*, and I don’t think the toaster and dishtowels were worth it. Besides which, it took her over a year to write a thank-you, and she was looking at that damn toaster every morning. (It was, though, fun for the shenannigans that those I shared 1/4 or more of my DNA with engaged in.)
So the question is - is this how most people perceive the “cousin terminology” and understand it? Or do they have it the wrong way?
