Solve two-gene dihybrid crosses by assigning gametes, predicting phenotypes and evaluating F2 or test-cross ratios in IB Biology HL D3.2.17.
In cats, the allele for curled ears (C) is dominant over the allele for normal ears (c). The allele for black colour (B) is dominant over the allele for grey colour (b). A cross occurs between two cats that are both heterozygous for these unlinked traits.
Using a Punnett grid, predict the ratio of phenotypes of offspring in the next generation.
a. Punnett grid correctly drawn / correct gametes;
b. phenotype ratio 9:3:3:1;
c. correct identification of expected phenotypes (9) black cats with curled ears, (3) grey cats with curled ears, (3) black cats with normal ears, (1) gray cat with normal ears;