# Solving Punnet Squares for Dark Hair & Brown Eyes

• mirandasatterley
In summary, the conversation discussed the use of Punnett squares to determine the possible genotypes of offspring based on the dominant and recessive alleles of their parents. Four possible combinations were listed for a red-haired woman with blue eyes and a dark-haired man with brown eyes, and examples of Punnett squares were provided for two of these combinations. The conversation also highlighted the importance of considering all possible combinations of parental alleles when setting up a Punnett square.
mirandasatterley
[SOLVED] Punnet Squares

The allele for dark hair D is dominant over that of red hair d, and the allele for brown eyes B is dominant over that of blue eyes b. A women is red-haired and has blue eyes. Her husband is dark-haired and has brown eyes.
a) What are the possible genotypes for the woman?
b) What are the possible genotypes for the man?
c) There are 4 possible ways to match the genotypes of these two individuals. In each of the 4 cases, draw a punnet square give all the possible genotypes for their offspring.

So I know that the woman must have alleles: dd and bb
the man must have alleles: DD or Dd and BB or Bb
the 4 ways to match the genotypes are:
dd,bb x DD,BB
dd,bb x DD,Bb
dd,bb x Dd,BB
dd,bb x Dd,Bd

For the match in bold writing, I'm not sure how to draw the punnet square.

How did you draw them for the other 3 matches? The concept is identical. I think I'll be able to see where you're running into trouble (and therefore follow up with the help you need) if you just show how you set up the Punnett square for either the second or third combinations in your list (skip the first one for now, I won't be able to tell as much from you showing that, unless you just want the practice to show me all of them).

for the second one:
dd,bb x DD,BD:
DB Db
-------------------------------------------------------
db DdBb Ddbb
-------------------------------------------------------
db DdBb Ddbb

For the fourth one:
dd,bb x Dd,Bb, I'm just confused because for the paternal alleles, Dd,Bb, there are many combinations: DB, dB, Db, and db, wheras for the other three punnet squares there were only 2 combinations? Oh I think its just because i was only writing two before when there are actually four options for all of them (some just repeat so I was leaving them out).

Thanks for making me realize i was doing it wrong!

mirandasatterley said:
Oh I think its just because i was only writing two before when there are actually four options for all of them (some just repeat so I was leaving them out).
Exactly! That's why I wanted to see how you were writing them out, because it would tell me if you were missing a more general concept, or just getting hung up on the last one.

Thanks for making me realize i was doing it wrong!
It's much better when you see it for yourself...now I'm willing to bet you'll never make that mistake again.

## 1. How do you determine the probability of a child having dark hair and brown eyes using Punnet squares?

To determine the probability of a child having dark hair and brown eyes using Punnet squares, you first need to know the genetic information (genotype) of the parents. The Punnet square is a tool used to show the possible combinations of alleles (genes) that can be inherited from each parent. By filling in the squares with the alleles for dark hair and brown eyes, you can determine the likelihood of the child inheriting these traits.

## 2. What are the steps for solving Punnet squares for dark hair and brown eyes?

The steps for solving Punnet squares for dark hair and brown eyes are as follows:

1. Identify the genotypes of the parents for hair color and eye color.
2. Write the alleles for each parent on the top and left side of the Punnet square.
3. Fill in the squares with the possible combinations of alleles from each parent.
4. Count the number of squares with the desired phenotype (in this case, dark hair and brown eyes).
5. Divide the number of squares with the desired phenotype by the total number of squares to determine the probability of the child inheriting these traits.

## 3. Can Punnet squares accurately predict the traits of a child?

Punnet squares are a predictive tool that can provide the probability of a child inheriting certain traits based on the genetic information of the parents. However, they cannot guarantee the exact traits that a child will have, as genetic variations and other factors can influence the expression of traits.

## 4. How can Punnet squares be used for other genetic traits?

Punnet squares can be used to determine the probability of a child inheriting any genetic trait, not just dark hair and brown eyes. The same steps apply, but the alleles and corresponding probabilities will vary depending on the trait being studied.

## 5. Are Punnet squares the only way to predict the traits of a child?

No, Punnet squares are not the only way to predict the traits of a child. Other methods, such as genetic testing and family pedigree analysis, can also provide information about the likelihood of a child inheriting certain traits. Punnet squares are just one tool that can be used to understand the genetic possibilities of a child's traits.

• Biology and Chemistry Homework Help
Replies
6
Views
5K
• Biology and Chemistry Homework Help
Replies
2
Views
8K
• Biology and Chemistry Homework Help
Replies
3
Views
3K
• Biology and Medical
Replies
12
Views
4K
• Biology and Chemistry Homework Help
Replies
2
Views
4K
• Biology and Medical
Replies
16
Views
140K
• Biology and Chemistry Homework Help
Replies
1
Views
3K
• Biology and Chemistry Homework Help
Replies
4
Views
7K
• Biology and Chemistry Homework Help
Replies
2
Views
3K
• Biology and Chemistry Homework Help
Replies
2
Views
7K