Question

When both the alleles in a heterozygous individual express themselves together in a mosaic pattern, it is called

• A. pseudo-dominance
• B. codominance
• C. Amphi-dominance
• D. Dominance

Answer 1

The correct option is B codominance

When both the alleles in a heterozygous individual express themselves forming a mosaic pattern of phenotype, it is called codominance. The two alleles of a gene produce two distinct gene products; a situation of codominance arises, where both the gene products are phenotypically detected.

The sudden appearance of a recessive phenotype in a pedigree, due to deletion of a masking dominant gene, is known as pseudo-dominance. It is the phenomenon in which a recessive allele shows itself in the phenotype when only one copy of the allele is present, as in hemizygous alleles or in deletion heterozygotes. Many of X-linked genetic disorders in males are pseudodominant. Since males receive one X chromosome and one Y chromosome, the recessive gene in the X chromosome leads to its expression.

Dominance means the phenomenon of expression of a trait even in the heterozygous condition.