Question

Q:-what will be the phenotype &gnotype ratio if we cross p/p;L/l*p/p;L/l ?

Answer 1

Genotypic ratio is 4:8:4 (or 1:2:1)

Phenotypic ratio is 12:4 (or 3:1)

Explanation:

This question isn't too hard - it's a 4x4 dihybrid cross. Let's just plug all of the values into a grid, and solve for our genotypes first:

From here, the values are clear. Of the 16 possible outcomes, 4 are for the genotype ppLL , 8 for ppLl , and 4 for ppll. Thus, our genotypic ratio is 4:8:4 or 1:2:1.

For our phenotypic ratio, we can simplify our gene expressions to a single letter, representing either a dominant or recessive expression of that gene. Doing this, we end up having 2 phenotypes present: pL (12) and pl (4). Thus, our phenotypic ratio is 12:4 or 3:1.