Question

Case: Purebred shorthorn cattle of white coat (WW) were crossed with purebred cattle of red coat (RR). The $F_1$ cattle had coats with patches of white and red side by side.
The same phenomenon is seen in:

• A. Height of pea plant
• B. Flower colour of snapdragon
• C. AB blood group of human
• D. All the above

Answer 1

The correct option is C AB blood group of human

Co-dominance is a phenomenon in which both the alleles of a gene are dominant and are expressed independently in a heterozygous condition. As a result, traits associated with each allele are displayed simultaneously. The red and white coat colour in shorthorn cattle are controlled by co-dominant alleles and due to this, their hybrid ($F_1$ generation) is of roan coat colour (RW) i.e., patches of white and red.
The same phenomenon is seen in AB blood group of human where both the alleles of A and B are co-dominance.