Question

Self fertilising trihybrid plants form

• A. Eight different gametes and 64 different zygotes
• B. Four different gametes and sixteen different zygotes
• C. Eight different gametes and sixteen different zygotes
• D. Eight different gametes and thirty two different zygotes

Answer 1

The correct option is A Eight different gametes and 64 different zygotes

A total number of types of gamete produced by an organism is 2${}^n$, where n is the number of heterozygous genes present. As we know that trihybrid plant is heterozygous for three genes, these total possible gametes by it = 2${}^3$ = 8. During fertilization, any of the 8 types of sperms can fuse with any of the 8 types of egg to produce 64 possible combinations of zygotes. This makes option A correct but C and D wrong. Four different types of gametes are produced by an organism who is heterozygous for two genes; 2${}^2$ = 4 and resultant four gametes produce total 4 x 4 = 16 zygotic combinations. Thus, option B is wrong.