I have a genetics question that might make me look super stupid

[Deminism]

If a child looks like someone in their family are they also likely to have their character traits and illnesses or are they inherited differently?

DD looks the spitting image of MIL. Does that mean she will be similar to her in other ways?

This seems like a v basic question but google not helping?

Yy, yesyesitsme.

If it's simple dominant/recessive Mendelian inheritance of a rare condition, then DH is a carrier, and each child has a 50% chance of being a carrier.

But surely if it was that simple, someone would have reassured OP, so I don't know.

My son looks like his dad and has his maths skills...: but has my personality and sense of humour.

My daughter looks like me.... but has her dads personality

Thanks for the search term @JamieVardysHavingAParty
I actually turned down genetic counselling when ttc as I was so desperate to have a baby, any baby. And now I think we are getting to the stage where it is DD’s choice not mine whether to find out

@Yesyesitsme DH has it in a v mild form so 100 per cent carries the gene.

Ah ok, so he's not just a carrier then. At what age would any symptoms start to appear?

The X chromosome doesn't actually change much over time so it will be exactly the same in a DD as her paternal grandmother.

This is really interesting and I think is linked to the fact that mutation is more common in the Y chromosome, yes? Does that then suggest that girls tend to have a closer similarity to their parents because they inherit 2 X chromosomes that are very similar to their parents copies, I wonder?

not necessarily
unless the visual likeness is a trait of an illness.

Nature versus nurture? No, she probably won’t be anything like her. Different environment.

My DH has his dad's looks and mum's personality. Glad it wasn't the other way round!

DS is very similar in looks and character to my DF who died when DS was 4mnths old. So genetics may play some part in personality, but apparently I look like my DM but I have my DFs personality. We recently found out we may have a genetically inherited condition, DM, Dsis and myself have variation of condition but are waiting for genetic testing. Since it is autosomal dominant there is 50% chance of children inheriting it so our extended family will need testing.

Clearly you are concerned enough to start a thread on here which suggests to me you need to get a referral to the genetics clinic to discuss it. We've just been through genetic testing for an enzyme deficiency which as it turns out has not been as simple as a leads to b equals c. Without the testing we wouldn't have known about genes being different but not expressing themselves as clearly theres other things going on.

Your daughter shares roughly 1/4 of your MILs genes. What they encode (and therefore which traits they 'cause' in your daughter) is random- so just because she's inherited gene(s) from MIL related to facial appearance doesn't necessarily mean that her personality is strongly shaped by genes inherited from MIL. There's also the whole nature/nurture thing relating to personality, which means that your daughter's personality will be strongly influenced by her environment/upbringing/life experiences.

Sorry, just read the updates re it being a genetic condition rather than personality as such. Second the comments re genetic counselling.

I think @JamieVardysHavingAParty has given you some excellent, knowledgeable advice - she (or he) is someone who clearly has an understanding of the subject (coming from someone else who also does).

can I suggest you check if there is a specific charity in uk which will give you more informed information? check with NHS if they mention/suggest or suggest one.

www.musculardystrophyuk.org/get-the-right-care-and-support/our-helpline/
a starting point??

And now I think we are getting to the stage where it is DD’s choice not mine whether to find out

Hmm, I see the dilemma, but I would say, seek that referral.

I don't think any similarity of appearance makes it more likely that your daughter will have the same health issues as your MIL, but I think you need a referral to a real-life person who knows this condition and can discuss it in as much or as little detail as you want.

Most people do better with more information than less.

I suspect that includes you, and there's nothing wrong with that. At the moment, the physical resemblance between your daughter and MIL has raised your concerns for her health, and I don't think those worries are going to go away because of some anon posts on a mumsnet thread, and rightfully so.

Stop trying to guess what the chances might be in your situation from online reading about the condition in general and make someone tell you.

Stephminx Thank you very much for saying so. Much appreciated. This year's off to a good start for me!

@ragged

As her daughter inherits a chromosome from each parent, in terms of genetic material she is 50/50 mum and dad.

However, as you say, the expression of genes can be modified at a number of levels (epigenetics, transcription, translation, RNA export etc).

X-inactivation is a process by which females shut down a single X chromosome. This happens randomly in development, and one cell might shut down the maternal X, and the other the paternal X, so you end up with a mix essentially. This is why Calico cats have a tortoise shell coat pattern depending on which X is inactivated. Biologically it would be risky for all cells in the body to shut off solely the male or female X.