Genealogy Chat

About a week ago here, on a discussion about whether one should 'waste time' on following sideways branches on trees, a member here said not only would he not do so, he'd also not bother doing his maternal grandmothers ancestors, because as a male child of his mothers he would share zero genetic material with her. I found this disturbing. First that's 25% of my tree (probably the most researched 25% as it happens) pretty much written off. Second my grandma was rather dear to me bless her, and to think I share no genetic material from her was a shock. I have not been able to find any info online that can either confirm or deny this. I'm certainly no expert on the subject..but did do genetics breifly at school , and as I remembered it you got half your genes from mum, half from dad...so therefore 25% from each grandparent? (or so I'd always assumed!) Perhaps someone could explain it for me, been bothering me for a week now this!.

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Hello, I am the daughter of Jackie and she asked me about this question so I thought that I'd provide some input that might help you out Regardless of what sex you are, you will contain genetic material from all of your grandparents... Let me explain... The concept that we get 50% of our genetic material from each parent is correct, however it is not necessarilly true that all genetic material from one specific parent will show as well as the genetic material from the other parent. It's a difficult idea to comprehend, but in simpler terms: Each egg and each sperm contains half the number of chromosomes (which contain the DNA/genetic material) than the parent. Each egg and sperm will recieve its genetic material from a random formation during cell separation - This is where differences come from - we have so many chromosomes that it's unlikely that two siblings will have the exact same chromosome inheritance. Further more, Chromosomes contain dominant and recessive genes. For example (a very simple example - hair is more complicated than this but i'm simplifying it down) - a gene for hair is inherited by both parents, that is, they provide a possibility for certain genetic material to be displayed. If your mother has brown hair and your father has blonde hair, you will inherit both genes, but will only display the dominant gene, in most cases, the brown hair. It gets even more difficult if a brown haired person that CARRIES the gene for blonde hair has a child with someone with the same genetic characteristic - this produces fully recessive characteristics as there is a 1/4 chance that the recessive (blonde) genes will combine in the zygote and produce a child that displays a different characteristic to both parents. To say that you dont inherit any characteristics from your grandparents is highly silly, as genetics are passed down generation to generation, however, to say that we inherit exactly 25% of one of our grandparent's genetics is slightly untrue - A lot of our genetic material is unique to us (as in, we haven't inherited it from either parent - this is what distinguishes us from another person during forensic analysis - even if we were in a murder investigation and the two suspects were siblings, Forensic analysts would focus on the 'non coding DNA' which is different regardless of relations to other people, thus, would produce a 99.9% positive chance even if the siblings were very similar) Whilst we will inherit 25% of the genetic material from each grandparent, the characteristics displayed in an individual aren't likely to be that simple - whilst we could inherit 25% of our material from one grandparent, it is possible that we only display 1% of that data, as the other 24% is dominated by a gene from a separate grandparent. I hope this helps you understand a little better. Everyone you find in your family tree you will have a slight genetic relation to - the closer they are to your direct family the more similarities there will be in the coding DNA - far distant relatives will have a much smaller coding-DNA similarity to you, but to say that you contain no genetic information from a specific side of your family or grandparent is completely silly... that is, unless you were a pure clone of one specific parent, which has never been attempted. ;) -Sarah

This from my daughter who is about to start studying forensic science majoring in biology. Also explains why my parents ( Both black haired ) had 3 children with black hair and one with pure almost snow white hair. My Grandfather was snow white! ( Unless my mother slept with the postman!!!LOL!) jackie

Richard, I saw that discussion a few weeks ago and remember thinking how mistaken that guy was. Anyway, Google 'Mitochondrial Eve'. That's just one example of DNA we get from the female side, regardless of our sex. Rose

I agree, very disturbing, I think the maternal side is the most rewarding. By the way the term is mitochondrial eve (lil typo there I suspect!). Thanks for that - wikipedia has a great bit about it! Cherilyn

So if I understand correctly, this guy was completely wrong as your just as likely to have as much genetic inheritence from either grandmother, whether dear grandma is paternal or maternal? Really doesn't make a difference as he seemed to suggest.

Cheryl, Just corrected the typo. Richard, I think he was confused and assumed all DNA is attached to the sex X and Y chromosomes. Rose

Hi all Most interested in your discussion I have researched many off shoots to my tree as i find along the line some are related to other branchs, a few of them married cousins, I find the argument that we are only 25% genetically matched to our grandmothers so why bother researching them quite sad, my maternal grandmother and her family are a huge part of my life. Our family trees are about our families surely not what dna we share, if that was the case how can we really be sure our grandfather or fathers really are our blood relatives without dna tests. lorraine

Do we also need to consider here what makes us the people we are? is it just our genetic make up? Or is it also the environment in which we grow, develop and hopefully prosper? Do we discount all non-blood relationships? What about step relationships and adoptions? My friend has two adopted children who share share no genetic material with her, but are so influenced by her that bit is striking. They even look like her in some ways, as they begin to acquire her mannerisms and tone of voice. genes are important, but we are more than simply our genetic make up. All the people in our families are important.

Also, what matters in my opinion is how you feel about that person- my Granddad was technically my step-grandad, but he brought my mum up as his own and was a massive part of our family, I would not dream of leaving him out of my tree just because we are not genetically connected, we are connected by the most important bond of all- love !!!

Whereas obviously you are going to feel a strong link with someone you know and love, no matter what the genetics, fair enough, it is hard to feel equally linked to say their ancestors one or two hundred years back, if your not actually 'genetically' related to them, so important to know I feel. Thanks for all the info, and Robert for putting my mind at rest!

Yes Richard I take your point about lack of connection, but we also need to bear in mind that as family historians we take much on trust as far as paternity goes anyway. This is why Judaism is carried by the female line. We can all be fairly sure who our mothers are!

Go from your grandmother, say she had ten children they are all related to her, so if your parents had ten children it does not matter how you put it on your tree but they are all related to her, and so on down the line, so anyone who says do not follow kids of aunts and uncles are distorting the facts there are related to you one way or other. ie cousins.

Roger, I agree totally. I follow every line I can, because far from being a name 'collector', often in the past I have thought a line was so distant not worth bothering with, only to find a link or marraige way down the line that in one fell blow opens up a flood of priceless info on my direct relatives. I think people who don't do this are shooting themselevs in the foot somewhat, perhaps without realising it. Certainly some of the very best info I have had here so far has been from very distant relations, rather than close ones.

As has been said, our genes come from all our blood ancestors, whatever their sex. Going down the twiglets has led to so many contacts and findings of e.g. marriages of cousins and so on, that a far more detailed tree has been built up far quicker than would have been possible by a skeleton tree (no pun intended0.

I went to a family history talk two weeks ago and it was on genes. He said the genes were easy to trace through the female line, you can go back centuries through the female line but it dosn't work with the male.

Sue Eh??? Why can't you trace males through their genes too? Did he explain this? OC

There is also the point that the female line is more likely to be 'true' than the male line!! The mother knows she gave birth to the child, but the 'father ' can't be sure it's his :o) maggie

Robert, And here I was thinking your beliefs might be due to some odd religious sect! :-) Rose