Final answer:
Offspring that are homozygous recessive for both traits will have genotypes consisting of two recessive alleles for each gene (e.g., 'aa'). In a typical cross of two heterozygotes, the expected genotypic ratio is 1:2:1, while the phenotypic ratio is 3:1, favoring the dominant trait unless the trait is a recessive lethal allele.
Step-by-step explanation:
The genotype for offspring that are homozygous for both recessive traits would consist of two recessive alleles for each trait, represented as 'aa' if we assume 'a' is the recessive allele. When performing a cross between two heterozygous parents (Aa), using a Punnett square, we can predict the ratio of homozygous dominant (AA), heterozygous (Aa), and homozygous recessive (aa) offspring. This typically follows a genotypic ratio of 1:2:1 and a phenotypic ratio of 3 dominant to 1 recessive if the recessive trait is not lethal. In cases where there is a recessive lethal allele, the expected ratio changes because the homozygous recessive offspring are not viable, and thus the genotypic ratio could be 1:2:0.