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"all In A Family"?


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#1 hazelm

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Posted 03 March 2018 - 06:05 AM

"Science uncovers the familial bonds that bind us."

 

Biology?  Computer Science?  News?  Well, news at least.  I'll put it here.

 

As a natural-born skeptic and as someone who spent years researching and assembling a family tree and finding all sorts of problems and contradictions in even court and church records - to say nothing of deliberate alterations by family members - I would very much like to hear some scientists' comments about this.  It does go into some fields of research about which I know nothing.   Especially how you find the DNA of someone who died in the 17th century and know it matches someone born in 1940.  Other questions are already popping in mind.  I'd better stop before I start.

 

https://www.scienced...p Science News)

 

 

Any thoughts from the better-informed?  Thank you.


Edited by hazelm, 03 March 2018 - 06:07 AM.


#2 LaurieAG

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Posted 04 March 2018 - 05:44 AM

The impression I received from reading the article was that no DNA research was actually used and the genealogy details used were sourced from people who had submitted their genealogy details with certain filtered exclusions. I'm not sure why they say "To try" and although there may be a present link between education/occupation and longevity the process described extends this 'link' back to 1600.

 

To try and untangle the role of nature and nurture in longevity, the researchers built a model and trained it on a dataset of 3 million relatives born between 1600 and 1910 who had lived past the age of 30. They excluded twins, individuals who died in the U.S. Civil War, World War I and II, or in a natural disaster (inferred if relatives died within 10 days of each other).

...

The researchers verified that the dataset was representative of the general U.S. population's education level by cross-checking a subset of Vermont Geni.com profiles against the state's detailed death registry.

 

My father extensively researched our family tree and managed to get records back to 1791 in Ireland. It's quite fascinating stuff.

 

Due to Irish naming conventions of the period, i.e. first son name after the fathers father, second son named after the mothers father and the third son named after the father, the names of the earliest persons father and grandfather can be identified even if no records are available. The same convention is used for female children via mothers and the fathers/mothers mothers names.

 

A genealogy also existed for the main branches of the family between circa 880 and 1580 and several surveys also named the heads of families and their locations in the 17th century so data could be generated for gaps leaving us with only 2-3 generations where we were unable to place names to our direct ancestors. Additionally, as our family had no 'famine designation' (a name added on the end to distinguish between separate branches i.e. Cooper, Peeler, etc among many other more distantly related family groups with the same name in the same area) we could also deduce that our family was the first to arrive in the area (the mountains between Tipperary and Limerick) after the Cromwellian confiscations in the 1650's while the others arrived later. 

 

Interesting enough the average age (with no exclusions) between father and first son in the ancient lineages between 880 and 1580 and that in the period between 1791 and 1959 (when I was born) where we have actual records were both 36 years indicating that the basic family longevity remained consistent for over 1000 years.

 

My great great great grandfather was born at the start of the potato famine, married at 40, emigrated to Australia during the american civil war and passed away in 1901 aged 81. Incidentally the majority of my ancestors main occupation was 'farmer' and my father tells me that my great great great grandfathers longevity was due to the fact that the soil on his farm wasn't suitable for growing potatoes so the family ate other vegetables that would be considered pig food by people in lowland areas where potatoes could be grown. 

 

Also being a 'farmer' doesn't necessarily exclude you from being educated as we have tracked down Irish Catholic leases (31 years or 1 English life) held by 2 brothers of a direct ancestor in 1791 and both signed their names (not with an X).   

 

So basic averages (like my recent NEO posts) may give rough generic data but there can be exceptions that vary greatly from these generic averages due to certain conditions in certain places in certain times and it is more likely that these exceptions are the families most likely to have consistent longevity/occupation 'links' going back to 1600 i.e. they are the exception rather than the norm. 


Edited by LaurieAG, 04 March 2018 - 06:02 AM.


#3 hazelm

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Posted 06 March 2018 - 03:01 PM

Did they not use any DNA records?  I though they did.  Maybe I didn't read it well.



#4 LaurieAG

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Posted 07 March 2018 - 03:48 AM

If you search for 'dna' in the article you'll find 2 references which have very little relevance to what they actually did.



#5 hazelm

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Posted 07 March 2018 - 04:41 AM

If you search for 'dna' in the article you'll find 2 references which have very little relevance to what they actually did.

All right.  The whole thing was confusing to me.  How reliable is DNA as an identifier?  Does it hold up in court?  I have often wondered.


Edited by hazelm, 07 March 2018 - 04:41 AM.


#6 LaurieAG

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Posted 08 March 2018 - 02:04 AM

For working out if a group of people have a common ancestor or working out if one person has dna identical to a dna sample it's not that bad but in court you cannot really use it on a probabilistic basis. From google 

 

 

Many courts have held that unless the finding of a match is accompanied by some generally accepted or scientifically sound profile frequency or probability estimate, no testimony about DNA testing is admissible. ... (suggesting that the better practice is not to refer to probability estimates when introducing DNA results).

 

 



#7 hazelm

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Posted 08 March 2018 - 04:58 AM

For working out if a group of people have a common ancestor or working out if one person has dna identical to a dna sample it's not that bad but in court you cannot really use it on a probabilistic basis. From google 

Thank you for that.  I mentioned my skepticism.  Here is an example of why.  You are reading the 1850 census.  You find your grandparents with four children.  You assume these are all children of your grandparents.  If you are lucky, you may later find a court record indicating that one of the children is actually the son of grandfather's deceased brother.  When brother died, grandfather took the child and reared him as his own.  That's if you are lucky.  Do you ever wonder how many neighbors or relatives took in orphaned children without going through court records? 

 

Back to your grandfather, how closely will the DNA of the "adopted" orphan match up to the rest of the family?  Grandfather and his brother had the same DNA but the child had a different mother.  Now what happens to the family tree?

 

It's little things like that which I feel make genealogy a fun hobby but wants a degree of caution.  I am glad to hear that the courts seem to take that caution.  Again, thanks.



#8 Turtle

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Posted 08 March 2018 - 07:19 PM

... Especially how you find the DNA of someone who died in the 17th century and know it matches someone born in 1940.  Other questions are already popping in mind.  I'd better stop before I start.
 
...
Any thoughts from the better-informed?  Thank you.

Locks o' hair lady. :hi: :ebluehair 
 
DNA from a lock of hair @ The Legal Geneologist

It’s absolutely possible to get DNA from a sample of hair. Scientists have used hair from ancient and aboriginal remains1 and even from a woolly mammoth2 to obtain DNA for testing. But that doesn’t mean you should go ahead and test that lock of hair from your great-great grandmother, because hair poses some problems in terms of what DNA you can get.
...


While that's iffy, exhumation of a corpse should meat the nead. :hal_skeleton: :beer:

#9 hazelm

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Posted 09 March 2018 - 02:27 PM

So, you are saying the hair lasts much longer and can be tested.  Right?  So do bones, thinking about the Egyptian mummies - to say nothing of they  dry climate.  I'm just not thinking - not making connections.

 

The whole answer is that I need to read more about DNA.  I have a light-and-easy understanding of what it is.  Maybe time to read a good book about DNA.   

 

Thank you.