What is the genotypic ratio for AaBB x AaBb
Did you see the Yahoo answer from yesterday?
When you look at the answers you have from making the crosses:
.. the genotypic ratio is the ratio of "letter combinations" in the Punnett square. For instance, if a monohybrid cross produces RR, Rr, rR, rr, then the genotypic ratio is 1 RR: 2 Rr: 1 rr.
.. the phenotypic ratio is the ratio of traits expected among the offspring. For instance, if R = red and r=white, then the RR, Rr, rR, rr outcome from the previous example would yield 3 reds and 1 white. The phenotypic ratio is 3 red: 1 white.
Dihybrid crosses are done the same way. It's just that dihybrid crosses have a 4x4 Punnett square and the ratio will be more complicated, like 9 green, round: 3 green, wrinkled: 3 yellow, round: 1 yellow, wrinkled.
The same question was on Wiki.
You might like to download the following PDF file:
archive.msstate.edu/dept/poultry/Lecture%203.pdf -
Sra