The observed distribution of offspring was: black-red 1,070; black-white 177; green-red 180; green-white 1,072. Based on these data, what is the recombination frequency?
A. 86%
B. 7%
C. 17%
D. 14%
E. 30%
Background Info:
In a particular species of mammal, black hair (B) is dominant to green hair (b), and red eyes (R) are dominant to white eyes (r). When a BbRr individual is mated with a bbrr individual, offspring are produced in a ratio of 5 black hair and red eyes : 5 green hair and white eyes : 1 black hair and white eyes : I green hair and red eyes.
Since Jiskha does not have a regular biology tutor, you might try this site.
http://biology-forums.com/index.php
If there is a tutor here who can help you with this particular question, I'm sure he/she will add a response.
The genes for hair color and eye color are linked
To calculate the recombination frequency, we need to determine the frequency of the recombinant offspring. Recombinant offspring are those that do not have the same combination of phenotypes as either of the parents.
In this case, the recombinant offspring would be those with either black hair and white eyes (Bbrr) or green hair and red eyes (bbRr).
Let's calculate the frequencies of these recombinant offspring:
Frequency of black hair and white eyes (Bbrr):
From the given data, we know that there were 177 offspring with the black hair and white eyes phenotype (black-white).
Frequency of green hair and red eyes (bbRr):
From the given data, we know that there were 180 offspring with the green hair and red eyes phenotype (green-red).
To calculate the total number of offspring, we add up the counts for each phenotype combination:
black-red: 1,070
black-white: 177
green-red: 180
green-white: 1,072
Total number of offspring = 1,070 + 177 + 180 + 1,072 = 2,499
Now, we can calculate the recombination frequency:
Recombination Frequency = (Recombinant Offspring / Total Offspring) * 100
Recombination Frequency = ((177 + 180) / 2,499) * 100
Recombination Frequency = (357 / 2,499) * 100
Recombination Frequency ≈ 14.2857 ≈ 14%
Therefore, the recombination frequency is approximately 14%.
The correct answer is D. 14%.