On the show last night, they did say that
(1) Hemophelia is a trait that is passed through the mother's bloodline and the perpetuity of the disease through royal bloodlines had nothing to do with inbreeding, it was just passsed on through the mothers' bloodlines.
(2) the risk of genetic abnormalities for a baby which is a product of incest is only about 2% greater than the risk for a baby of non-realted parents.
I am not going to spend hours searching the web to verify these facts, b/c (a) I am at work and actually have a task at hand, (b) I only have a sister and could not breed with her anyway, and (c) I think the concept of incest is pretty skanky [but I also think the concept of people like Britney & Fed-Ex procreating is grody, so take that for what it is worth]. But if anyone can prove or disprove the facts thrown out last night, post it here and enlighten us all, please. THANKS!
I THINK you might be right about the the 2% thing -- that sounds like what I've read elsewhere. (I'd be curious if anyone knows for certain) That was why I said in an earlier post that the risks involved in inbreeding (at least involving a single instance, not repeated instances down a bloodline) are MUCH smaller than a lot of people think.
Actually, on that note, there are lots of areas around the world where first-cousin inbreeding is perfectly acceptable, if not almost the norm. There are some risks (much smaller than the already small risks for siblings) for first cousins, but yet, there is no universal cultural taboo against it. In fact, for some societies this kind of inbreeding seems to offer some positives, in that it strengthens family bonds across different branches of the family tree without too much risk of genetic abnormalities. Also, it is interesting to point out that different societies have different definitions of family "closeness" -- there are some in which, for example, your dad's brother is considered as "close" as your own brother/sister, therefore, you are not allowed to marry him because that would be "icky" incest. Whereas other societies, not icky. And yet others, it's "icky" to mate with your mom's sister's husband (or whatever, just giving examples). In other words, this whole thing about "universal taboos" is not as clear cut as we might think, since there are so many different definitions of what a "close" relative is and what counts as incest. I do think there have been some societies historically that have considered brother-sister inbreeding as somewhat acceptable.
Anyway, the point is that there isn't any "natural law" about these sort of things, much as some people might think. On that note, most animal species are (at least sometimes) incestuous, so it is not "unnatural" and nor are isolated incidences of it a death sentence for a species.
Re: hemophilia -- you are right and not right. It is passed through the mother's bloodline. Whether it is related to incest or not just depends -- usually no, sometimes yess. I don't know what happened with the british royal family, but I think I read that was an isolated mutation (there was no history of it in the families involved until one particular queen who passed it to her sons-- can't remember which one). However, if you take a brother and sister who are both recessive for hemophilia and they interbreed, then well, the incidence of their sons developing it is quite high (like 25 percent?). Obviously, this doesn't happen a lot -- usually it is just two unrelated people who get together and have children and have no idea they both happen to be recessive for it.
There is a reason that these relationships are taboo. I am grossed out by how common the 1/2 brother/sister tried to make their relationship sound. There are internet communities full of people in this type of relationship
I get the heebie jeebies just thinking about it.
Job well done!
