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A researcher hypothesizes that in mice, two autosomal dominant traits, trait Q and trait R, are determined by separate genes found on the same chromosome. The researcher crosses mice that are
heterozygous for both traits and counts the number of offspring with each combination of phenotypes. The total number of offspring produced was 64. The researcher plans to do a chi-square
analysis of the data and calculates the expected number of mice with each combination of phenotypes. Which of the following is the expected number of offspring that will display both trait Q and
trait R

Respuesta :

Answer:

Explanation:

If we consider the traits Q and R individually, then

P(Q) = 75%  (Q is dominant, from hetero-zygous parents)

similarly

P(R) = 75%  (Q is dominant, from hetero-zygous parents)

Assuming the two alleles P & Q are indepedent, then

P(Q and R) = 75% * 75% = 56.25%

Out of 64 offsprings, we expect 75*56.25% = 9/16*64 = 36 express both Q and R traits, on the average.

For the given experiment 36 offspring out of 64 will produce both Q and R traits.

Di-hybrid Cross:

It is cross of organisms in which scientist perform the experiment keeping two traits in mind.

One parent is pure and dominant while another is Heterozygous for traits.

The parental genotypes will be,

RRQQ   x   RrQq

The gametes will be,

 RQ, Rq, rQ, and rq

The cross,

            RQ            Rq         rQ         rq

RQ      RQRQ      RQRq      RQrQ     RQrq

Probability, If the traits Q and R expressed

P(Q) = 75% (Q is dominant, from heterozygous parents)

P(R) = 75%  (Q is dominant, from heterozygous parents)

Probability, if two alleles P & Q are independent, then

P(Q & R) = 75%  x 75% = 56.25%

The offspring that express both alleles, out of 64 offspring,

[tex]\bold {75 \times 56.25\% = \dfrac {9}{16\times 64} = 36 }[/tex]

Therefore, for the given experiment 36 offspring out of 64 will produce both Q and R traits.

To know more about di-hybid cross,

https://brainly.com/question/12289852