Blue eyes and genetics.?


Question:
Both my husband and I have blue eyes.so we expected and got 2 children with blue eyes too.(colour ranging from very light to dark blue but never mind).
I come from a family where everybody has blue eyes too.but I met 2 couples who produced at leat one brown eyed kid (and no.don't think there was a question of sperm donor). One couple even had 3 kids looking like them but all brown-eyed..and both parents had blue eyes..
I am not asking about cheating , extra-marital affairs here..but I was always taught that 2 blue-eyed people could only produce blue-eyed kids..Curious..hope somebody from biology or medecine can answer that !! I thought that when you had a recessive gene..etc..for medical people.
Thank you for your answers.

Answers:
The blue eye gene can simply be a broken brown eye gene. Most of the time though it is a normal gene that is passed down and doesn't change. If someone has one regular blue eye gene and one "broken" brown eye gene, then they will have blue eyes. If the "broken" gene is passed down to their children, the body sences something wrong with the gene and fixes it when it is passed down to the children. Then some of their kids could have brown eyes. I hope I answered you question well!

Other Answers:
it has to do with dominate and recessive genes.

check this out it is kinda interesting!

http://www.athro.com/evo/gen/genefr2.html

Several genes determine eye colour. These genes affect the amount of pigment in the iris of your eyes but some have stronger effects than others. Two brown-eyed parents could still have blue-eyed children. In the parents, the effect of the blue-eye gene is masked by the brown-eye gene, but they may still pass on a blue-eye gene to their children. A child who inherits no brown-eye genes but gets two blue-eye genes will have blue eyes.

This is the case with our family. My mom has blue eyes and my dad had brown eyes = me with brown eyes. However, my husband and I both have brown eyes = our daughter with blue eyes.

The gene for brown eyes (B) is dominant, meaning just one brown-eyed gene passed along from your parents will give you brown eyes. The blue-eyed gene (b) is recessive; you must receive two blue-eyed genes in order to get blue eyes.
So, my husband and I must both have the Bb genotype, passing along our recessive blue-eyed gene (b) to create a "bb" genotype in our daughter.

Hope that helps!
Source(s):
http://www.sciencemuseum.org.uk/exhibitions/genes/166.asp



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