Final answer:
The question is about genetic ratios in a dihybrid cross. The ratio is 1:1:1:1 for the gametes produced by F1 heterozygotes in a cross of AABB and aabb. Other genotype ratios are given for different genetic crosses, with the F2 generation phenotype often following a 3:1 dominant to recessive pattern unless other inheritance patterns are present.
Step-by-step explanation:
The question concerns the Mendelian inheritance in genetics, specifically addressing a dihybrid cross. The ratio of the F1 gametes (AB, aB, Ab, ab) produced by the F1 heterozygotes (AaBb) in a cross between AABB and aabb is 1:1:1:1. This is because there is an equal probability of inheriting either allele from the heterozygous pair due to the law of independent assortment, given no gene linkage.
When crossing two heterozygous individuals (Aa), the genotype ratio in the next generation is 1 AA : 2 Aa : 1 aa. The phenotype ratio, depending on the dominance of the alleles, will typically be 3 dominant : 1 recessive, unless other inheritance patterns like incomplete dominance or codominance are at play, which might alter the expected phenotypic ratios.