Match the Missing Numbers in the Following Phrase

Short Answer

Match the missing numbers in the following phrase. Relationships between phenotype and genotype become increasingly complex with the involvement of increasing numbers of genes. Consider two genes. When heterozygotes for two genes are mated, there are usually 9 different genotypes and [A] different phenotypes in the offspring. When two gene products are active in the same process or pathway, non-standard phenotypic ratios can occur instead of the usual 9:3:3:[B] ratio. For example, if both gene products A and B are needed for phenotype X to be observed, and the recessive alleles do not make gene products, in a cross between AaBb and AaBb, then [C] offspring will display phenotype X and [D] offspring will not display the phenotype.