Whose DNA do I have?

Post by **SarahND** » Mon Mar 23, 2009 1:05 am

Still, to look on the bright side and try to stem the tide of despair at the overwhelming amount of work still to be done, I do have the strictly maternal line back to my mother's mother's mother's mother's mother's mother's mother's mother... It's all the father's mothers whose lines peter out after a generation or two (at the most four, in a couple of lucky cases). Good thing I enjoy the hunt!

Sarah

ksyoung · Post by **ksyoung** » Mon Mar 23, 2009 6:18 am

Your X chromosome is neither your grandfather's nor your grandmother's, but a mix of the two. That's because of cross-over (translocation) that happens normally always between paired chromosomes when germ cells (egg and sperm) are being made.

That's why siblings share ON AVERAGE 50% of genetic information, but that 50% can skew to more or less depending on how the chromosomes cross.

From a geneticist...

Miss Poohs · Post by **Miss Poohs** » Mon Mar 23, 2009 9:20 am

All I know is my son has all MY endearing qualities and all my husbands irritating ones

.

mallog · Post by **mallog** » Mon Mar 23, 2009 9:36 am

Miss Poohs wrote:All I know is my son has all MY endearing qualities and all my husbands irritating ones .

I've found that's how it works too

Post by **SarahND** » Mon Mar 23, 2009 3:37 pm

ksyoung wrote:Your X chromosome is neither your grandfather's nor your grandmother's, but a mix of the two. That's because of cross-over (translocation) that happens normally always between paired chromosomes when germ cells (egg and sperm) are being made.

That's why siblings share ON AVERAGE 50% of genetic information, but that 50% can skew to more or less depending on how the chromosomes cross.

From a geneticist...

Thanks for that! It makes more sense. It seemed a bit odd that I would have nothing from my paternal grandfather (especially since my sister looks quite a bit like him, and my daughter has "all the irritating qualities" of hers!)

Or, are you referring only to the maternal grandparents?

Regards,
Sarah

winslowsmom · Post by **winslowsmom** » Mon Mar 23, 2009 5:51 pm

https://genographic.nationalgeographic. ... posts.html

Here is another site that has good tutorials about DNA and genetics.
I found it when I enlisted my brother to participate in a surname study using his DNA.

Dennis · Post by **Dennis** » Mon Mar 23, 2009 5:56 pm

Wow!

That x chromosome is really getting me baffled. To put it bluntly, how much of me is my mom's dad and mom? I'm thinking of getting one of those DNA tests done, but don't know if I should get both the X and Y tests.

dennis

Post by **SarahND** » Mon Mar 23, 2009 6:29 pm

Okay, this is making more sense now. Thanks for that link, Winslowsmom. It is only the part of the dna that is used for testing that comes straight down unmixed, and that is why it is easily testable. The rest is the mixture that makes us the individuals we are. So, for a man, the y-dna test will show the father's father's father's etc. and the mt-dna test will show the mother's mother's mother's etc. for both men and women. This does not mean that that is all there is in our makeup, just that these are the things that are easiest to test.

As far as which tests you should have, Dennis, I guess that depends on your resources and how curious you are! The y-dna test will give you more specific information on people of your surname and it is hoped will tie you in with others of the same name (if not, you've got more research to do!). The mt-dna test gives more general results, not linked to specific families, but rather of populations in the past.

Regards,
Sarah

Dennis · Post by **Dennis** » Mon Mar 23, 2009 7:36 pm

Even though I've gone back, on my mom's side, some 10 generations going from her to her dad then his dad and so on then that info is is no longer of use to me but only to my mom's male siblings. I had gone back about 5 generation Xs of just my mom's mom and her mom etc. On my dad's side I've gone back about 5 generation Ys until they hit Ireland, then nothing.

despondent dennis.

Post by **SarahND** » Mon Mar 23, 2009 7:50 pm

Dennis wrote: On my dad's side I've gone back about 5 generation Ys until they hit Ireland, then nothing.

Then maybe the y-dna test would help you with this search. If you match up to others who were able to take the surname farther back, then it could be very useful!

And your mother's side is still part of you, they just haven't developed the test that will extract any information about it.

As far as being despondent, if it were never worthwhile to research a family that is not directly relevant to oneself, then nobody would ever get any help here on TS!

All the best,
Sarah

TalkingScot.com

Whose DNA do I have?

chromosome crossovers

Re: chromosome crossovers