DNA Testing - Why Not

[california dreamin]

The following link is to an Irish DNA project - it outlines what I feel is one of the many worthwhile reasons for doing DNA testing (and I personally find very interesting).  I do understand this particular project will only be of interest to those of us with Irish roots.  I would love to participate in a project such as this one except that all 8 of my great-grandparents are not from Ireland

http://www.rcsi.ie/index.jsp?p=100&n=110&a=1966

ps
Here is another link that some of you may find interesting:

http://www.facebook.com/DNAday

[grandma]

I can understand why some aren`t interested in doing a test, but in my case I had an illigitimate grandfather. We were rather lucky as his middle name was Lynch and there was no reason for this. Just along the street there was an Irish shoemaker James Lynch, and we joked for years that he was the  guilty culpruit. did some searching for this James Lynch and found a bit more info but decided to do the DNA, and since then found a far out cousin in the US with the last name Lynch.  Hope more Lynchs will do the test too.

Some might say it s looking for the needle in the haystack but it`s worth it in the end.

Mary

[Flattybasher9]

What I read into it is, if the recorded father is not the biological father, or the recorded mother is not the biological mother, then the back-tracking of past generations gets confused. Once data is confused, and results are extrapolated from said data, then the wrong conclusion(s) is/are inevitable. It's like history. It's only the point of view of the person who recorded it. It was thought up until recently that mtDNA is maternally inherited, but the latest research is showing that this may be a wrong conclusion. It could be paternal in some cases.

Regards

Malky

[Redroger]

What I read into it is, if the recorded father is not the biological father, or the recorded mother is not the biological mother,

My problem in a nut shell, but so far neither side know in whose line the culprit is.

[nickgc]

Malky,

Please provide some scientific journal references for your claim that males can pass on mtDNA.  Unless you are talking about bivalves rather than humans, I don't think you will be able to.

I am aware of a single study, of a single individual, where the researchers claim this happened.  It was done 10 years ago.  One case does not make for a generalizable claim.  As far as I know, nobody claims that that mtDNA can be inherited from the paternal line.  Science requires that claims be backed up with evidence, and that studies can be replicated, before they are accepted as providing valid conclusions.

Nick

[Flattybasher9]

"It was thought up until recently that mtDNA is maternally inherited, but the latest research is showing that this may be a wrong conclusion. It could be paternal in some cases.

Here's one, there are others if you look :-

http://biology.ucsd.edu/classes/old.web.classes/bimm100.FA04/lecture/Paternal_mtDNA.pdf

Regards

Malky

[Nick29]

One of the inherent problems with DNA is that it is very easily compromised by contamination from other samples.   This becomes even more of a problem when samples are taken at home by non-professionals under less than ideal conditions.  There's an amusing story of Interpol trying to trace a woman whose DNA pattern was found at a number of murders and other crimes across continental Europe.  To their credit, the police eventually traced the woman..... to a factory making swabs for DNA tests 

[nickgc]

Thanks Malky, but the study you cite is the exact same one I am aware of from 10 years ago.  Nothing in it implies that we should distrust current mtDNA testing in its possibility for giving us valid maternal lineage information.

Mitochondria are what provide the necessary chemical energy for cells.  A human (female) egg contains an estimated 100,000 to 1 million mitochondria.  A human (male) sperm cell contains 100 to 1000 of them.  And all of those in the sperm cell are contained in the tail (flagella) to help propel the little bugger on his way to the goal. Once a sperm enters the egg, the tail disconnects, so those mitochondria cannot enter the egg.  If it happens it is a one in a million fluke (I made up that number, but it is definitely rare enough that we don't need to consider it for genealogical purposes.)

I hope you read the paper you cited so you can see how even these researchers declare what an abnormal occurrence it was to find such a thing.  Read especially the second to the last paragraph where they refer to a "pathogenic mutation that gave this one or few mitochondria a selective advantage".

Nick

 

[Flattybasher9]

Yes, I did read it, and I also read the 2002, 2004 and 2005 research papers.

Regards

Malky