Genotypic ratio?

Question

what is the Genotypic ratio of Rr*Rr

what is the Phenotypic ratio?

Answer 1

Rr x Rr

RR, Rr, Rr,rr
i/e/ the genotypic ratio is 1:2:1 (homozygous dominant: heterozygous dominant: homozygous recessive)

phenetypic ratio 3:1( dominant : recessive, unless incomplete dominance is displayed in the expression of this character in which case the ratio will be 1:2:1)

Answer 2

Genotypes are what letter code (in this case there are 3 possibilities eg RR, Rr or rr) you get.
Genotype determines the phenotype (what is "looks" like or how it functions...sometimes I say the phenotype is like a photo....).

In this case with just dominant (R) and recessive (r) alleles you are only going to have only 2 phenotypes. Because R is dominant, the genotypes RR and Rr will show the same (dominant) phenotype and rr will show the recessive phenotype.

There are only limited combinations you can get with this cross. Doing a punnet square will show you what the combinations are. I think its better that you actually carry out the cross.
When you have done so, count up the number of RR, Rr and rr. If your results are for example: RR RR Rr and rr, your GENOTYPE ratio will be 2:1:1 (as opposed to a percentage of 50% RR, 25% Rr and 25% rr).
In this example the ratio of PHENOTYPES will be 3:1 (remember the genotypes RR and Rr will produce something that LOOK the same as each other).
Good luck

Answer 3

i think

R r
R RR Rr

r Rr rr
phenotype 75% R 25% r
genotype 3/4 R 1/4 r

thats how i learned it