[doc30]

My wife hd an interesting experience in her freshman biology class where simple genetics like this were discussed. The prof mentioned that if both parents were brown eyed, their children would be brown eyed. One girl raised her hand and argued against this because she had blue eyes and her parents both had brown eyes. The prof went into the detailed explanation and the girl ran out of the cloass crying.

Turns out she was adopted and wasn't told. She guessed in in class and left to confront her parents that confirmed it. Talk about a surprising way to learn somehting like that!

[ccmay]

That's complete crap. Two brown-eyed parents can definitely have a blue-eyed child.

[Scutter]

The prof mentioned that if both parents were brown eyed, their children would be brown eyed.

Except this is not necessarily true. Using the simplistic model, the blue gene is recessive. So both parents could have brown eyes, but both have a recessive blue gene. The child could then get the blue gene from each parent and have blue eyes. So it doesn't prove the kid was adopted.

[wintertime]

you must have the colors reversed.

The adopted girl must have had brown eyes, and her adoptive parents brown. Two blue-eyed parents can NOT have a brown eyed daughter. Impossible.

Why? The reason is that blue is a recessive gene and the combination of one blue gene with a brown gene yields the dominant color of brown.

[wintertime]

The adopted girl must have had brown eyes, and her adoptive parents brown.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

that should read: The adopted girl had brown, and the two parents had BLUE. Two blue eyed parent can NOT have a brown eyed daughter.