Question

Study the following and identify the wrong statement.

• A. The probability of homozygous dwarf progeny formed in a cross involving $TT\times Tt$ parents is $0.75$.
• B. The probability of homozygous tall progeny formed in a cross involving $TT\times TT$ parents is one.
• C. The probability of heterozygous tall progeny formed in a cross involving $TT\times tt$ parents is one.
  
• D. The probability of homozygous dwarf progeny formed in a cross involving $TT\times TT$ parents is zero.

Answer 1

Answer: (A)

The probability of homozygous dwarf progeny formed in a cross involving $TT\times Tt$ parents is $0.75$.

As per Mendel's law of segregation, during gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene. An offspring thus receives a pair of alleles from both the parents for expression of a trait. In given example, the first statement has one homozygous and one heterozygous gene. The progeny formed after crossing will be TT, TT, Tt and Tt. As per the law of dominance, all progeny are tall. So the first statement is wrong.

In statement B, progeny formed are TT, TT, TT, TT, all tall and homozygous.

In statement C, progeny formed are Tt, Tt, Tt, Tt, all tall and heterozygous.

In statement D, progeny formed are TT, TT, TT, TT, no dwarf progeny.

Thus, the correct answer is option A.