What is the phenotype ratio for a recessive trait in Mendels F2 generation?

Answer 1

Asuming that the F1 generation is heterozygous for a single trait and that the F2 cross is of 2 F1 offspring. Ex. Aa X Aa the phenotypic ratio is 3:1 dominant to recessive. The genotypic ratio is 1:2:1 AA:Aa:aa.

Answer 2

This depends on how closely linked they are as well as the initial genetics of the

parents for each gene locus.

If the genes are close enough together that the chance of them crossing over is virtually zero and one parent is homozygous dominant at each locus and the other is homozygous recessive at each site the ratios would essentially match the results expected for the F1 generation, where all individuals would be phenotypically dominant for both characteristics, with all offspring being AaBb. There is not phenotypic/genotypic ratio here as all individuals are heterozygous with a dominant phenotype.

The F2 generation is where the law of independent assortment would not operate and

offspring would be either phenotypically dominant or phenotypically recessive for both traits...AB and ab would transmit as if they were a single gene.

There would be no A-bb or aaB- individuals produced in this example.

The ratio here would be 3:1 3 phenotypically dominant to 1 phenotypically recessive.

If the parents were AAbb and aaBB (again assuming that the alleles are so closely linked there is zero chance of crossing over) the F1 generation would again be phenotypically identical to the F1 generation of the original example and the offspring would all be genotypically the same AaBb...however, the F2 generation would be different than expected because the crossing of 2 AaBb individuals would produce

phenotypes/genotypes AAbb,aaBB or AaBb but not AABB or aabb as would be expected with non-linked traits. No phenotypically and therefore genotypically homozygous recessive individuals will ever be produced from this mating.

Here the ratio is 1:1:1.

Answer 3

1:1 :)

Answer 4

3.1 - Apex