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Was Habsburg chin even caused by inbreeding?
This guy is Charles V that was a product of 2 generations of outbreeding with no prior known blood relationship between descendants, so well before their family tree started to look like a circle.
Prognathism is not some super rare 1 in a million recessive gene, it's pretty common dominant gene (like 2-4% of appearing in adults). Obviously with today's medicine it can be fixed to some extent so it doesn't look that bad. Even if you straight up got your sister pregnant, the chances of inheriting a dominant gene jumps from 50% to 75% on average. A significant increase, but far from the cause of them being deformed right?
So isn't Habsburg chin in worst case scenario just a dominant gene that circled back ? Doesn't Charles V paintings disprove them being massively deformed just because of inbreeding? Could someone please help me understand it, because i'm kinda lost with this one.
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I have to admit I'm as confused as OP by all the upvotes for people apparently talking about a different Charles and all the downvotes when OP reiterates which Charles they're asking about. Is there something relevant that everyone except OP and me knows about Charles V (as opposed to Charles II who is naturally famous among geneticists)? What is the family tree of Charles V? All I can find in a few seconds is that his parents were from two different European royal families - their marriage was the one that sealed the alliance of Spain and Austria - though of course that doesn't necessarily mean they were unrelated.
At any rate, inbreeding vs. a rare dominant trait aren't two mutually exclusive scenarios. Inbreeding makes it more common you keep any genetic trait in the family. The reason why we mainly discuss rare recessive alleles as the consequence of inbreeding is because those are the ones that are very unlikely to express their phenotype except in the case of inbreeding; their risk from inbreeding is a very big step up from outbreeding, while a dominant allele gives you 50-50 odds with any mating partner.
Op: Look at this guy, he's not inbred
Reddit: You're talking about the wrong guy because you clearly meant to talk about the inbred guy
He wasn’t the product of 2 generations of outbreeding. His father was his mother’s uncle and his grandmother was also his aunt. Not sure where you got the idea of outbreeding from. He prominently inherited his conditions due to the 16 generations of inbreeding previous to him.
You are mistaking Charles V with Charles II of Spain. I am talking about the person from left branch in 2nd generation. No one from his known descendants was indicated to be an inbreed.
If you look him up in Wikipedia, then start looking at his predecessors back to even when they were just dukes, you see SO many first cousin marriages. It’s how they kept land and titles in the family.
Newer research proposes recessive genes affecting the facial structure (along with other issues). It's proposed the chin was caused by inbreeding as the severity of prognathism correlated with the inbreeding coefficient. Even then, the inbreeding coefficient only accounted for 22% of prognathism severity. https://www.tandfonline.com/doi/full/10.1080/03014460.2019.1687752
Thanks for the article. I remember reading it not so long ago. I had hard time understanding this article back then. My understanding of genetic inheritence is limited. From what i know in order to express a recessive trait both parents need a faulty copy of a gene. Then and only then you have 1/4 chance to be affected and 1/2 chance of being a carrier.
I just have hard time understanding how Charles V recessive trait could survive that long considering that he even had childrens with unrelated person. From my research prognathism, also known as Habsburg jaw is a dominant gene. Then again my knowledge about genetics is limited, so if you might help me understand how it works i would be really grateful.
Good point, wish I was knowledgeable to comment further.
Comment deleted by user
Thanks for the data, but it looks like we are talking about a different person here. I am talking about Charles V here, not Charles II. The only thing that i question is whatever or not their famous chins were pyproduct of inbreeding or not. That being said i'm really grateful for providing me some data on this subject.
Was Habsburg chin even caused by inbreeding?
Yes.
It most likely helped perserving their prognathism, since they kept that dominant gene in the family. That being said, since Charles V had it even without inbreeding it's unlikely that the gene was a recessive mutation. What i'm trying to say is that they didn't looked deformed solely because of incest. Their chins weren't really invented by their inbreeding. I think that it's most propably was caused by a pretty common dominant gene. That being said, if you have some proofs to back your claim i will gladly read them.
Charles V was inbred, his mother, Jauna's (Joanna's) parents (Isabella and Ferdinand) were second cousins, and his father was not inbred as far as I can tell, I'm not going back further than that though but I'm willing to bet there were more cousin marriages just because that's what royal families did to keep claims.
I'm not really sure about your question here though. It's obvious that the chin being so prominent in the family line was caused by the progressive inbreeding after Charles V. Charles V probably just had the prominent chin and genetic disorder because it ran in the family, you're right about that, but as the line continously married cousins to cousins, nieces to uncles the genes that ran in that family took it over for the worst and made the chin one of their defining features.
For you to be inbred, your parents must be related to each other. If your mother's parents were related, your mother is inbred. If your mother has you with a father she is not related to, you are not inbred. You aren't inbred just because one of your parents is.
Second cousins is literally nothing in terms of inbreeding.
I don't think you know what inbreeding means, it doesn't mean your parents must be related to each other, where did you get that definition? Because by that definition many many royals would not be considered inbred by the fact that they're parent weren't related but their grandparents were. I could be wrong, but most definitions don't exclude families who have inbred grandparents or parents.
While the risk is small, it isn't nonexistent, and it can possibly explain Charles V's chin. Second cousins can share 3% of their DNA, so the possibility of the child being born with a disability because of the genetic risk is increased by second cousin inbreeding, meaning because Jauna was inbred she possibly passed these "bad genes" to her son.
Eat your words, lol. Don't tell someone they don't know what something is when you're wrong. I know what I'm talking about.
https://nature.berkeley.edu/classes/espm-103/Ballou-Inbreeding%20Coefficients.pdf
For one individual to be inbred, their parents must be related. If their parents aren't related, then they aren't inbred. If your maternal grandma is related to your paternal grandma, you are inbred. If your paternal grandparents are related to each other but not to anyone on your mom's side, your dad is inbred, but you are not.
Second cousins do not matter when it comes to inbreeding. Look at birth defect statistics. Second cousinhood is nothing - and even if it was significant, that just means one parent is inbred. The child themselves is not inbred, because mom and dad aren't related.
Your study is from 1997, that offers one man's prospective, not a definition, because a the definition of inbred simple means what J D Ballou states at the beginning of the study, "Inbreeding can be loosely defined by any mating between relatives."
"The coefficient of inbreeding (COI) is a number measuring how inbred an individual is. Specifically, it is the probability that two alleles at any locus in an individual are identical by descent from a common ancestor of the two parents."
Not really a definition for the actual word, just for the calculator.
2. All of the sources I site here say that second cousins do in fact have an increased risk of genetic anomalies in their children. No matter how small, it is an increased risk, because second cousins do share DNA.
https://www.thetech.org/ask-a-geneticist/articles/2015/risk-second-cousins-having-child-disability/
https://link.springer.com/referenceworkentry/10.1007/978-1-4020-6754-9_8397
https://www.bmj.com/content/365/bmj.l1851
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3419292/
Just reminding you that:
you talked down to me when I was correct
you then claimed that my correction was not relevant to your comment when I was literally directly addressing your comment
If this were real life, you would know you owed me an apology. But since this is the internet and I'm not a human face to you, you feel no need to acknowledge that you talked down to me.