Genetics and grandparents

Yes, that's correct, janthea. After parents, grandparents are the closest genetically.

Thought so. I didn't want to pass this gem on to daughts unless I was sure of facts. Thanks baggy

Its when people talk about their great, great, great,great grandparents that things start to get dodgy!!!!! work it out

janthea, STOP! I've just checked. Carbon's comment made me do the sums . Your grandchild is equally related genetically to its blood uncles and aunts as to its grandparents because each of those people has 50% of their parents' genes, as does each of your daughters. They don't have the same 50%, but it's still 50%. All your grandchildren will have 25% of your genes and 25% of each of the other grandparents.

Baggy - I remember being told once (I think it was about obstetric history and inherited likelihood of a difficult pregnancy and birth) that you were more likely to take after your father's mother in respect to female characteristics than your mother's mother because (thinks hard) your x chromosome from your mother could be from her mother or her father's mother, but the one from your father has to be from his mother - otherwise he'd have been a girl, and not your father at all.

ie - 50% chance of inheriting from your father's side, two lots of 25% from your mothers side, either her mother or her paternal grandmother.

My quick and easy deliveries were clearly from my dad's mother, (only 20 mins in hospital for each of my second and third shots - just made it).

That's interesting, elegran. Sounds as if you chose your OH well, at least as far as childbirth outcomes!

That's interesting Elegran. In my case my eldest daughter was a breech birth, my mother mentioned that she had two breech births. My eldest daughter's first baby was in a breech position (she had a caesarian). I always thought a breech could be inherited but recently I was told that having a breech birth would not be inherited, so I don't know now....

Many years ago there was a program on TV called 'Meet the Ancestors', where archaeologists investigated ancient remains, and sometimes reconstructed skulls. Once they did one in a village somewhere down South, called a meeting in the village hall and asked if any local resembled the reconstruction. They all nominated one man who really DID look like his ancient ancestor. Another time they did a DNA check and the local history teacher was shown to be a descendent from hundreds of years ago - in fact if I remember rightly if was from pre-history.

Well I know that DD was born with the same birthmark on her leg as my mother.

She was my mother's first grandchild and I think it made her extra special in my mum's eyes.

I have identical feet to my father's sister - short big toe and long second toe which makes shoe buying an experience to avoid.

Joan That TV programme was fascinating.
Faye I wonder whether your family's breech births have something to do with the shape of your innards, which would be inherited, or the babies' preference for being awkward - which I suppose could be inherited too.?
Soupy The birthmark has nothing to do with your reproductive history and x or y chromosomes, so not likely to be biased in the direction of one or the other grandparent, of course. It is all statistics, it determines nothing in individual cases.
Baggy In this case it was my mother who chose me a useful father. Not sure it was that useful a characteristic - zooming across town to try to beat the contractions is not a restful experience. But both my daughters had long and complicated deliveries - as did their paternal grandmother. Interesting.

Both my DDs were back to back presentations and their DC (3 between them) have all been back to back. My father, myself, one DD and my neice all had an extra right canine tooth and my mother, myself and DD1 all had a mole in the exact same place on the right breast.

Also my DH and DD1 can wiggle their ears in a spectacular manner. We did know that his Uncle (father's brother) could do it too but were amazed to discover at said Uncle's funeral how many of the nieces, nephews, cousins and grandchildren could demonstrate the same quirk. It was very bizzare!

Re inheriting x chromosomes - this would only apply if there were genes controlling childbirth on the x chromosome. They are beginning to suss this stuff out now. But there are another 22 possible chromosomes.
Funny things though, genes - On my DH side, one nephew looks exactly like his grandfather - same small build, Irish skin and red hair, facial features the lot. The other nephew is an absolute image of my DH, a bit like his mum and not at all like his dad. DH and nephew are both build like the proverbial brick outhouse and his mum and dad both have, small bones, light build. Tis indeed weird how these things work out.
There are two ways in which we can inherit down the maternal line rather than maternal - one is mitochondrial genes - genes that are not on chromosomes but are passed via the ovum. The other is something called epigenetics that is just coming into vogue... I think the idea is something like this - if, for instance, a mother is malnourished then certain genes will be expressed differently in her children - e.g. slower growth. This makes sense biologically as it would be a bad idea to have have big children when food is scarce. etc etc Prenatal influences - 21st Century style.

I think I read somewhere recently that inheritance wasnt necessarily 25% of each grandparent. Grandmothers passed on 30% of their genes to their daughter's daughter.

sort of on the same subject!
I was born by forceps on a friday 6 days before my paternal grandmothers birthday. three years ago my GD (daughter"s child) was born on a friday, by forceps, 6 days before my birthday. genetics or just weird coincidence?

The forceps might be genetics but the other two...!?

There is a neat statistical demonstration where the lecturer asks the class (of 30 or so) what they think the odds are of two people in the class having the same birthday. He then gets each to give their birth date, and Hey presto! there is usually at least one pair of "twins". He then goes on to prove mathematically what the odds are, and the answer is surprisingly likely.

I, my two sisters and both my sons were born on the expected date of delivery. How likely is that?

Three of my grandaughters are the spitting images of past generations in my family.
GD3 has a strong resemblance to my paternal grandmother, she has her red hair and quick Irish temper.I have a photo of one of my maternal greatgrandmothers, I never knew her as she died before I was born, and her face shape and features are an exact copy of those of GD4.She was my mother's father's mother.
GD1 is begining to show a strong likeness to my DH's mother.She was also of Irish descent but dark haired.

We recently found an old photograph of my grandfather (age 21 in 1917). We were amazed at the likeness to my 25 year-old son. I never would have made the connection since G'dad as I remember him looked nothing like my son. We'd never really worked out who son resembled but there's no doubt now that it's his Great Grandad!

Similar thing in my family, em. DD2 always had 'her own face'. Then one day her paternal grandfather was showing her some pictures of his parents. She looks just like his mother, he great grandmother. DD was so relieved!

All very interesting - having identical twins grandsons makes genetics even more interesting for me. However, the point I was trying to make was how diluted we are after only a few generations which makes tracing family trees
s beyond a couple of generations a bit pointless e.g. if you end up pretty soon looking for 64 grandparents - and you get 25% from your grandparents so that is 1.56%. I think! From then on it is miniscule and you are probably related to Ken Dodd and Sadam Hussain as well...............

If you do the maths we are all pretty much descended from everyone who was alive a few hundred years ago. Pity Will Shakespeare didn't pass on a few original manuscripts to me. Just the one would have been fine.

The genes from any one ancestor will, of course, become fewer with each generation, but not all genes are equal. Consequently, you have these interesting examples of very separate generations with a strong resemblance that people have described here.