Question

A cross involving two pairs of contrasting characters is called as___________

• A. Dihybrid cross
• B. Monohybrid cross
• C. Trihybrid cross
• D. Tetrahybrid cross

Answer 1

The correct option is A Dihybrid cross

• Monohybrid cross-refers to the inheritance of a single contrasting trait by two parents at a time. For example, a cross of tall (T) and dwarf (t) pea plants is a monohybrid cross as it exhibits the inheritance of plant height (TT x tt). Dihybrid cross-refers to inheritance of two pairs of contrasting characters by two parents at the same time.
• For example, the cross of two pea plants one with yellow and round seeds (YYRR) and other with green and wrinkled seeds (yyrr) exhibits the inheritance of seed colour and seed shape (YYRR x yyrr). Likewise, the inheritance of three or four traits by two parents at a time refers to trihybrid and tetrahybrid cross respectively.
• Example, inheritance of plant height, seed shape and seed colour (TTYYRR x ttyyrr) and inheritance of plant height, seed shape, seed colour and flower colour (TTYYRRWW x ttyyrrww).