Question

In a Mendelian cross between two heterozygous pea plants (Tt x Tt), where "T" is the dominant allele for tall plants and "t" is the recessive allele for short plants, what is the probability of obtaining a short plant?

• A. \( 0 \)
• B. \( \frac{1}{4} \)
• C. \( \frac{1}{2} \)
• D. \( 1 \)

Hint:

In a Mendelian monohybrid cross, the possible genotypes and phenotypes can be predicted using a Punnett square. For a recessive trait to be expressed, the individual must be homozygous recessive (tt).

Answer 1

The Correct Option is B

In this problem, we are dealing with a Mendelian inheritance pattern, where the trait of plant height (tall vs. short) is determined by the alleles "T" and "t". The "T" allele is dominant for tall plants, while "t" is recessive for short plants. When two heterozygous plants (Tt) are crossed, the possible genotypes of the offspring are as follows: 

1. The genotype of the parents is \( Tt \times Tt \). 

2. Using a Punnett square to determine the offspring's genotypes:  The possible genotypes of the offspring are: - \( TT \) (homozygous dominant, tall) - \( Tt \) (heterozygous, tall) - \( tt \) (homozygous recessive, short) 

3. The probability of obtaining a short plant, which must have the genotype \( tt \), is 1 out of 4 (or \( \frac{1}{4} \)). Thus, the probability of obtaining a short plant is \( \frac{1}{4} \).