What would be the probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant?

Question

What would be the probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant??  
A. 25%  
B. 50%  
C. 75%  
D. 100%

NursesPath · Accepted Answer

Correct Answer: (B)50%. 
Rationale: The probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant is 50%.This is a classic Mendelian genetics problem involving a single gene with complete dominance, where the allele for tall (S) is dominant over the allele for short (s). The short plant has a homozygous recessive genotype (ss), meaning it can only contribute a recessive 's' allele in its gametes. The tall plant is heterozygous (Ss), meaning it can produce two types of gametes with equal probability: one carrying the dominant 'S' allele and one carrying the recessive 's' allele. A Punnett square for this cross (ss x Ss) shows two possible genotypic outcomes for the offspring: Ss (when the tall parent contributes 'S') and ss (when the tall parent contributes 's'). Each of these outcomes has an equal 50% probability. The Ss genotype results in a heterozygous tall phenotype.Explanation of the Cross:The short plant (ss) can produce only one type of gamete: s.The tall plant (Ss) can produce two types of gametes: S and s, each with equal probability.The possible offspring genotypes from a cross between ss and Ss are:Ss (tall, heterozygous): occurs when the tall plant contributes S and the short plant contributes s.ss (short, homozygous recessive): occurs when the tall plant contributes s and the short plant contributes s.Since the tall plant's gametes are equally likely (50% S and 50% s), and the short plant always gives s, the probability for each genotype is 50%. Thus, the probability of a heterozygous tall (Ss) offspring is 50%.ConclusionIn a cross between a homozygous recessive individual and a heterozygous individual, the offspring genotypes will always reflect a 1:1 ratio of heterozygous to homozygous recessive. Since the tall parent in this cross (Ss) produces 'S' and 's' gametes in equal proportions, and the short parent (ss) only produces 's' gametes, the chance of any given offspring inheriting an 'S' from the tall parent (and an 's' from the short parent) to become Ss is 50%. This fundamental monohybrid cross pattern is key to predicting inheritance probabilities.

What would be the probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant?

A
25%

B
50%

C
75%

D
100%

The probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant is 50%.

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What would be the probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant?

A 25% B 50% C 75% D 100%

The probability of a short pea plant (ss) and a tall pea plant (Ss) producing a heterozygous tall pea plant is 50%.

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Related Questions

A
25%

B
50%

C
75%

D
100%