Watched Castle. Switched at birth.

[conuly]

Seriously, did anybody NOT see that coming? You'll notice I didn't even bother with a spoiler warning.

Here's a hint. If the big reveal is going to revolve around somebody's baby not being their biological kid, stop doing that "light-haired parents, dark-haired kid" thing. Everybody does that when doing adoption or switched at birth or whatever, and it's cool, except that it ruins the twist ending. So if we're not intended to figure out the plot of the episode 10 minutes in, sacrifice convention and have everybody running around with the same color hair for a change!

Also? Everybody and their dog knows that two blond parents don't have brunet kids. Of course, everybody knows a lot of things that don't turn out to be true, granted*, but all the same - with that bit of knowledge firmly implanted in the cultural consciousness, how can these people be so! shocked! to find out that their kid isn't genetically their kid?

Why isn't this up on TVTropes on their entry on "Switched at birth"?

*I don't even know if it's true or not anymore. Sorry.

Comments

[sayga.livejournal.com]

You know what's crazy? My cousin and her husband both have blue eyes, and all of THEIR parents have blue eyes too...and their son has brown eyes. They talk about the impossibility all the time. How can it happen? Besides her cheating, which if it happened she certainly doesn't admit it and is quite willing to discuss the statistics of genetic eye color with various eye-colored parents and all, so I really don't think she did. They are just as baffled as the rest of us.

[conuly]

LOL. My mother was in high school bio class when she heard that bit about how blue-eyed parents can't have dark-eyed kids, and asked "What about me?" Her mother's eyes are green and her father's were gray (or maybe it's the other way around?) and she has brown eyes. When she tells this story she ends with "And my teacher sort of hemmed and hawed and never DID answer the question!" but more prodding reveals that a week or two later the teacher came up to her privately and explained she'd done a LOT of research (clearly the whole incident had been weighing on her mind, although my mother says - and I believe her! - that the concept of her mother cheating on her father never occurred to her) and my mother's eyes aren't *brown* they're *hazel* and it's a different situation.

And so they *are* mixed colors, her eyes, if you look closely. (Besides, I'm so much like my grandfather it's not even funny, and I'm told I look a lot like my grandmother when she was young, so whatever.)

[marveen.livejournal.com]

I always found it odd and funny that the books in high school bio were written like there were only two eye colors, brown and blue. I've got hazel eyes, my father has green eyes, I've met people with grey eyes alla time. (I suppose genetically grey equates to blue, but still.)

I don't pay much attention to hair color because with the wonders of modern chemistry anybody's hair can be any color tomorrow.

[conuly]

Not on TV it can't. If it could, how would we know who was switched at birth with whom?

[sayga.livejournal.com]

True! My biology teacher said there are only 2 true eye colors: blue and brown. Everything else is a mixed color. My eyes are greeny grey blue and so are kira's. Daniel's look pure blue. I bet one of my cousins has some kind of mixed eyes, it's just weird because their son's eyes are so brown they're almost black!

[velvetchamber.livejournal.com]

Your teacher was not correct (I am speaking here as a student of genetics that is very interested in pigment biology). One can only really say that there is one predominant eye pigment, eumelanin, and the amount of that pigment and possibly the general thickness of the iris is what determines eye colour. The red of blood can also affect eye colour when there is very little eumelanistic pigment to hide the red.

The spectrum violet-grey-blue-green-hazel-brown-darkbrown is mostly dependent on the amount of eumelanin, with dark brown representing a very thoroughly pigmented iris and violet representing the least amount of melanin, so little that the eye colour is changed from light grey to violet by the colour of the blood vessels within the eye. Then I presume that the patchwork of hazel eyes is mostly due to the slightly varying thickness of the iris, or inequal eumelanin production within the iris.

Then the genetics of all of this is quite complicated, and not at all as straightforward as people once thought. Eye colour is not a trait dictated by a single locus, or even only a few. There is a myriad of loci that affect eye colour, but some loci have a much, much bigger effect than others, and that is what misled people in the beginning.

[sayga.livejournal.com]

I'm not sure what you said, but thank you for correcting my mis-information. :) I am a student of creative writing so genetics is just a curiosity for me, not something I know a lot about. But I can write you a nice sonnet. Haha!

[conuly]

I think I get it.

1. There's only one pigment that has to do with eye color. Your eye color depends largely on how much of that you have, and maybe how thick your iris is. It's like drawing a picture with only a charcoal pencil - you can still do shading, but you're doing it with that one tool.

2. There's a gene to reduce how much pigment you have. There's several of them. Your cousin has one type of pigment reducing gene - let's call it light. Her husband has another. LIGHT. Since they don't match, they do largely bupkis together, so their kid ended up with dark eyes. (I imagine this goes doubly so if the genes that reduce pigment are in different locations, in which case he could get a "have dark eyes, like normal folks" gene from each parent without any problems.)

3. You never heard about this in high school bio class because a. your teacher wasn't a geneticist b. they didn't know this yet and/or c. high school bio classes are stuck on basic Mendellian inheritance and have no interest in going beyond that.

I'm sure velvetchamber can point out my mistakes.

[velvetchamber.livejournal.com]

So, to answer this predicament, this can easily happen if the blue eyedness in this case is because the eye pigment reducing mutations that your cousin carries are not the same as the mutations that her husband carries. Then their son happens to get "good copies" of the different genes from either parent, so that he gets brown eyes. He could then expect to have pale eyed children, in particular if he winds up siring them with a pale eyed woman.

[queenlyzard.livejournal.com]

IIRC, blond is recessive, so two brunettes could have a blond kid but not the other way around.

[conuly]

Yeah, well, as the eye color discussion indicates it may be more complicated than that.