Wrt to Horowski's comment that Fritz is a great example of how first cousins marrying can end up perfectly fine, I wanted to elaborate a bit on the genetic possibilities here.
If you assume that FW had porphyria, that G3 had porphyria, and that some of the FW/SD kids had porphyria--and none of those diagnoses are confirmed, as far as I know--*and* you assume they all had the same type of porphyria (there are several), then the following scenario is possible.
Abbreviations:
p: the defective copy of the gene that causes porphyria. N: the normal copy of the same gene.
Since porphyria is a recessive trait, we would conclude that symptomatic FW had two defective copies of the gene.
FW: pp
And that asymptomatic SD had one defective copy and one normal copy (she's what we call a "carrier"):
SD: pN
And their kids, who get one copy from each parent, would have a fifty percent chance of getting two defective copies and being symptomatic (symptomatic pairings are in bold): pp, pp, pN, pN. (I thought about doing the Punnett square, but didn't want to waste time on the html--I have another post coming that's going to require some visuals.)
Whereas if FW and SD were not first cousins, then there would be a much greater chance that SD would have two normal copies of the gene, and the kids would all be asymptomatic carriers (who should then not marry their cousins): pN, pN, pN, pN.
The problem may or may not have been exacerbated by the fact that FW's parents were second cousins, and that that was through a line that included Sophia of Hanover, mother of G1. In other words, the fact that FW had two copies to make him symptomatic and to give his kids a 50% chance of being symptomatic may be related to his parents each carrying at least one defective copy of the same gene (p) that G3 had two copies of and SD one copy of.
Disclaimer: This is all assuming there is one porphyria-causing variant of one gene in the Hanovers and Hohenzollerns, all of which is speculation. I've also toned down the technical terms severely here.
Oh, and this is why in my unwritten reincarnation modern AU, Fritz gets gene therapy. :D
Let me add here that the later Hohenzollern are even more inbred because of all the repeated Braunschweig and Hessen-Darmstadt marriages. And then Friedrich of Hohenzollern marries Victoria daughter of Queen Victoria (herself daughter of a son of G3), thereby reuniting the two porphyria lines, and creating that wonder of emotional balance, Wilhelm II, aka Willy. As well as the current bunch locked in a law suit against the state of Brandenburg in order to get either their palaces or financial compensation for same. Talk about necessary gene therapy!
Ha! Yes, my biology background is not nearly as horrible as my history background and could follow it without the Punnett square written out :)
Inbreeding: a good possibility you'll end up with someone who doesn't have problems (or at least is only a carrier of problems which isn't such a big deal if they're gay gay gay and not going to reproduce, I guess). But also a good possibility you'll end up with someone who does :P
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timeasmymeasure
Inbreeding
Date: 2021-01-31 03:05 pm (UTC)If you assume that FW had porphyria, that G3 had porphyria, and that some of the FW/SD kids had porphyria--and none of those diagnoses are confirmed, as far as I know--*and* you assume they all had the same type of porphyria (there are several), then the following scenario is possible.
Abbreviations:
p: the defective copy of the gene that causes porphyria.
N: the normal copy of the same gene.
Since porphyria is a recessive trait, we would conclude that symptomatic FW had two defective copies of the gene.
FW: pp
And that asymptomatic SD had one defective copy and one normal copy (she's what we call a "carrier"):
SD: pN
And their kids, who get one copy from each parent, would have a fifty percent chance of getting two defective copies and being symptomatic (symptomatic pairings are in bold): pp, pp, pN, pN. (I thought about doing the Punnett square, but didn't want to waste time on the html--I have another post coming that's going to require some visuals.)
Whereas if FW and SD were not first cousins, then there would be a much greater chance that SD would have two normal copies of the gene, and the kids would all be asymptomatic carriers (who should then not marry their cousins): pN, pN, pN, pN.
The problem may or may not have been exacerbated by the fact that FW's parents were second cousins, and that that was through a line that included Sophia of Hanover, mother of G1. In other words, the fact that FW had two copies to make him symptomatic and to give his kids a 50% chance of being symptomatic may be related to his parents each carrying at least one defective copy of the same gene (p) that G3 had two copies of and SD one copy of.
Disclaimer: This is all assuming there is one porphyria-causing variant of one gene in the Hanovers and Hohenzollerns, all of which is speculation. I've also toned down the technical terms severely here.
Oh, and this is why in my unwritten reincarnation modern AU, Fritz gets gene therapy. :D
Re: Inbreeding
Date: 2021-01-31 04:36 pm (UTC)Re: Inbreeding
Date: 2021-02-12 05:31 am (UTC)Inbreeding: a good possibility you'll end up with someone who doesn't have problems (or at least is only a carrier of problems
which isn't such a big deal if they're gay gay gay and not going to reproduce, I guess). But also a good possibility you'll end up with someone who does :P