Inheritance: Mendel, Genetic Terminology, And Single Trait Crosses?

In humans, dark eyes (such as brown) are domiant over blue eyes. Janice has blue eyes. Robert has brown eyes. Robert's father has blue eyes.





a)The genotype of Janice is


b)The genotype of Robert is


c)The chances that Janice and Robert having children with blue eyes are?





This is in regards to ratios and results and possibly suing a punnet square.





I am not asking fr anyone to DO my homework, but it is a good wat to check my answers and help me. I am doing Bio 12 thru correspondese and appreciate the help.

Inheritance: Mendel, Genetic Terminology, And Single Trait Crosses?
brown eyes could be either BB or Bb and blue would have to be bb


janice has blue eyes so she has to be bb. if roberts father has blue and robert has brown then his father has to be hetero--Bb so that would leave robert with Bb as well.


if robert and janice have children the punnett would be Bb X bb


so 2:4 would be Bb-brown and 2:4 would be bb-blue
Reply:It's always essential to have sources cited for readers to refer to!


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Reply:D = dark


d = blue





a.) dd


b.) Dd


c.)


d d


D Dd Dd


d dd dd 50% chance of having a child with blue eyes or 1/2
Reply:if dark eyes are D


and blue eyes are b





a) bb


b) Db or DD





not sure about c
Reply:a) bb. Janice has to be "bb" because blue eyes is a recessive trait, and she would not express it unless she had two recessive alleles.


b) Bb. Robert has to have at least one dominant allele because he expresses the dominant brown eyed phenotype. However, we know that Robert must be heterozygous because he had to receive one recessive allele from his father.


c) 1/2. There is a 1/2 chance that their children will have blue eyes. A simple punnett square with Bb X bb will reveal this.

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