Can someone explain DNA to me?!

[Jungfraujoch]

So my maternal grandmother was Swiss but I don’t know the nationality of my maternal grandfather. If he also was Swiss how would this affect my DNA? Both my parents were born in the UK.

As I understand it, if your maternal grandparents were both Swiss, your Mother would be genetically Swiss and depending on the nationality of your Father, you'd either be Swiss or half Swiss.

as above, but there is really no such thing as "genetically swiss". Youre heritage will be half swiss

My father was born here. It’s my maternal grandfather I don’t know about - whether he was Swiss or English.

DNA is not specific to countries it may be classified as north European for example

Exactly. You can't be genetically Swiss. Switzerland only became a country in 1848! Obviously DNA goes back way further than that.

You're almost thinking about it the wrong way round.
When a baby is made, yes I'm going there, they get half their DNA from their mum and the other half from their dad. Their DNA doesn't change when they cross arbitrary geographical boundaries. So you are half your mum, and therefore a quarter of your maternal grandmother, who you know is/was a Swiss national. You don't know about your paternal grandfather so you are one quarter unknown DNA-origin.
As PPs have said, you can't tell someone is/was genetically Swiss or English or anything else, by their location of birth, adopted or preferred nationality.
Statistical analysis of thousands of people's DNA will identify clusters of people with similar DNA meaning they can be classed as people from a certain area which may be what you've picked up in thinking about your grandparents' "Swiss" DNA.

Yes, my DNA result shows 100% North and West European with Switzerland (Bern) indicated which ties in with my maternal grandmother. Additional ethnicity groups UK/England which is obviously my Dad (medium). I wondered if the reason it’s 100% is because my maternal grandfather was also Swiss?

Thanks for the info!

Most likely your grandfather was from North and West Europe. If it's been picked out in particular, you likely have more than one close relative who is/was genetically similar to people centred around Switzerland. So that could be your paternal grandparents, or other unknown genetic relatives that could have come from there and boosted the Swiss-centring part of your DNA.

I don't think the 100% North and West European with Switzerland (Bern) indicated can pin down a grandparent's nationality. More likely it tells you that he wasn't african or chinese or anything like that. He might still have been Austrian or German.

There genetic analyses are fun, but if you really want to know where he came from you probably want to get into genealogy and find his birth certificate. That would tell you a lot more.

Sadly impossible! Mum was adopted, never knew anything until she told us when she was in her 70s. Happily I found her Mum’s family (some cousins) but they had no idea about my Mum or who was her father. Mums birth certificate only has her Mum’s name.

these DNA companies tell you very little - they are collecting data from you rather than giving data to you

North and West Europe covers a large area (including the UK), and an area of constantly switching national boundaries and a fair bit of population mobility.

When one of these ancestry DNA companies says 'this DNA is from X region', what they mean is that there are reference genes in the sample that are most commonly found in people now living (and taking DNA tests) in that area.

It doesn't mean everyone there has them, or that people from elsewhere don't have them, or that the current reference population is genuinely representative of the historic population (particularly for places like Turkey/Greece or India/Pakistan/Bangladesh where there has been recent mass migration of specific groups from one region to the other).

If you keep an eye on the results over time, you'll probably find the ethnicity estimates vary as the databases are updated.

And on top of that, there's the complication of random inheritance.

You inherit half your genes from each parent. They inherited half their genes from each of their parents. But that doesn't mean that you have 4 neat quarters from each grandparent. On average, across a large sample, that will be the case - but not on an individual level because the 2 halves in each parent were throroughly stirred up before being passed on to you. So the DNA you got from your mother might have come exactly half from each grandparent, but the chances are you have a bit more from one side than the other. It's even possible (very occasionally) that it all comes from your grandmother and none from your grandfather.

And even if evenly inherited, all the previous generations contribute to the mix. If you have 1/4 'Swiss' markers, that might mean you have 1 Swiss grandparent. Or 2 great grandparents. Or 1 great grandparent and 2 great great grandparents etc, etc

Looking for familial genetic DNA matches listed in genealogy databases and going down the genealogy worm hole might help you gain a better understanding of "where you are from". It's time intensive, addictive and consuming but fascinating.

OK, you've got me. How could all the DNA come from a grandmother but none from the grandfather? Are you talking about the statistic possibility of it, or through something like Trisomy X?

Imagine 2 'grandparent' bags of 100 balls - 1 all white and 1 all black.

Take 50 from each bag and put them into 1 'parent' bag.

Then give them a good stir, close your eyes, and take 50 from that bag and put them into a 'child' bag.

Do it 100 times, and on average the child bag will have 25 white balls and 25 black ones. But generally it won't be an exact split and there will be 24:26, or 20:30. And very rarely the bag will be all black or all white.

(I'm excluding sex chromosomes from that analogy - obviously Ys are always male to male and don't mix in the same way. But I think standard genealogy DNA doesn't look at the Y - you need a separate test for that.)

You also need to consider that the countries that Swiss people come from (bad wording) like France, Germany etc dna testing either isn’t legal or widespread. Essentially you are relying on people being and interested, paying their money and actually taking the test. I suspect it’s going to be a waiting game of perhaps quite a few years before you get better results. I hope your mom has tested as you will get better results from her.

Sadly Mum is no longer with us. It took a lot of research to track down her cousins and I had a lot of help from so many wonderful people along the way. It really was a miracle all I had was my grandmothers name and that she came from Switzerland to have my Mum and then went back. No DOB or indication whereabouts in Switzerland she was from. But now I have extended family there who we visited when mum was alive which was just incredible.

And to further complicate things, in reality the grandparent bags aren't the starting point and aren't all one colour. And family lines cross and knot together over the centuries - especially in places where geography (such as lots of mountains) discourages dating outside the immediate area. So your grandparents may well already have a sprinkling of white balls in the 'black' bag and vice versa.