Phenotypes, Genotypes, and Eye Color

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Phenotypes, Genotypes, and Eye Color

Post by sfossen1 » Wed Jan 25, 2012 2:34 pm

Hello all,

I have a question that I'm working on for a college biology assignment. My dad's mom and dad both have brown eyes, but all 3 of their children have blue eyes. I have no information on my great grandparents. I need to know what the genotype would be for each individual so it would be:

my dad's dad: brown eyes
my dad's mom: brown eyes
my dad: blue eyes
my aunt: blue eyes
my uncle: blue eyes

Here is the the specific wording on my assignment:
-If an individual in the family shows a recessive trait but the parents both show the dominant trait, what would be the genotypes of each individual?

I have done so much research and I am just not finding any info on this. Most of the sites I go to say it is impossbile for 2 parents to have brown eyes and the children all have blue eyes. If anyone could help me on this, I would greatly appreciate it!!!!!

Thank you & have a good day!!!

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Inland Taipan
Inland Taipan
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Post by JackBean » Wed Jan 25, 2012 2:44 pm

you should read this ... /index.htm

consider, for simplicity, that there is only 1 gene with brown and blue alleles. The brown allele is dominant over blue allele. If a person has brown eyes, what are possible genotypes? If a person has blue eyes, what are possible genotypes?

Cis or trans? That's what matters.

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