# Quick Answer: How many phenotypic classes are present in the F2?

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Two Mechanisms Help Ensure That Mitosis Always Precedes Cytokinesis

## How do you find phenotypic classes?

There is a range of phenotypes, but most of the offspring are similar in color to the parents. If n = the number of gene pairs, then (2n + 1) will determine the total number of categories of phenotypes.

## What are phenotypic classes?

The four phenotypic classes correspond to the genotypes: A_B_, A_bb, aaB_, and aabb. If either of the singly homozygous recessive genotypes (i.e. A_bb or aaB_) has the same phenotype as the double homozygous recessive (aabb), then a 9:3:4 phenotypic ratio will be obtained.

## How many phenotypic and genotypic classes are possible?

8 Phenotypes and 27 Genotypes.

## How many types of phenotype and genotype will be formed in F2 generation?

F2 showed 4 different phenotypes: the round and yellow traits did not stay linked to each other. Ratios for each trait corresponds to what one would expect from monohybrid crosses. Shuffling of traits occurs before they realign in every possible combination.

## What is the phenotypic variance of the F2 generation?

The F2 generation have a phenotype variance of 3.0 for the number of abdominal bristles.

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## How do you count phenotypes?

Write the amount of homozygous dominant (AA) and heterozygous (Aa) squares as one phenotypic group. Count the amount of homozygous recessive (aa) squares as another group. Write the result as a ratio of the two groups. A count of 3 from one group and 1 from the other would give a ratio of 3:1.

## How many different phenotypes are possible?

Figure 13: The possible genotypes for each of the four phenotypes. Even though only four different phenotypes are possible from this cross, nine different genotypes are possible, as shown in Figure 13.

## What are the 3 types of genotypes?

There are three types of genotypes: homozygous dominant, homozygous recessive, and hetrozygous.

## How many phenotypic classes are expected in the progeny of a four point test cross?

How would a geneticist work with a four point test cross? There would be sixteen phenotypes in the progeny as a result of the hybrid parent making two parental gametes and fourteen recombinant gametes. These recombinant gametes would be a result of single, double and even triple crossovers that occurred in prophase I.