One parent with the genotype of Rr and another with the genotype rr would have offspring of Phenotypes?

Question

in a ratio of??

a. 3:1

b. 2:1

c. 1:1

d. all of one phenotype

Answer 1

b

they would produce 2 of Rr and 2 of rr, so they would be 2:1

Answer 2

Phenotypic Ratio = 1:1 (50/50)  

Potential Combinations (Offspring) =  Rr   Rr   rr   rr

Explaination:

The Phenotype is the way in which the genotype expresses itself.  

R and r can represent many things, such as, hair colour, attached or detached ear lobes, hair line, height, or to put it simply the "appearance" or expression of a gene.

The capital 'R' means that it is dominant and overpowers the small 'r' which is recessive.

    For Example:

           R = brown eyes

            r = blue eyes

            Father = Rr  (brown eyes)              sperm = 'R'  or   'r'

            Mother = rr   (blue eyes)                 egg = 'r'   or   'r'

Since the mother contributes half of her genetic material in her egg and the father contributes half of his genetic material in his sperm, there are four possible outcomes for offspring:

     Rr    Rr (brown eyes)                              rr    rr  (blue eyes)

            

Remember, 'R' (brown) is dominant and over powers the 'r' (blue), when an offspring is Rr he/she will only express the dominant trait. This case would result in a  1:1 (50/50) phenotypic ratio.

Look up:

- Punnet Square

- Gregor Mendel

Answer 3

C] 1:1

Phenotype refers to the physical appearance..hence is doent matter the allelic composition of the offspring.

Lets work out the cross to understand better:

Parents:          Rr       X        rr

Gametes:    R,r                  r, r

F1:                 Rr, Rr, rr, rr

As it cn be seen tht there are 2 "Rr" and 2 "rr"... hence the ratio is 2:2 or 1:1

the person who has answered b4 me is wrong...