In a species of flowering plant, red flower color is dominant to white flower color, where R is the dominant allele and r is the recessive allele. What is the expected phenotypic ratio of the offspring from the cross Rr × Rr
3 red-flowered plants: 1 white-flowered plant
In a monohybrid cross of Rr × Rr, the expected phenotypic ratio of offspring is 3:1, where three plants exhibit the dominant red flower color and one plant exhibits the recessive white flower color. This ratio arises from the combination of alleles in the offspring.
This choice accurately reflects the expected outcome of the cross. When two heterozygous plants (Rr) are crossed, the possible combinations of alleles in the offspring are RR, Rr, Rr, and rr. This results in three offspring with red flowers (RR, Rr, Rr) and one with white flowers (rr), producing the 3:1 ratio.
This choice is incorrect because it reverses the expected ratio of phenotypes. In the cross Rr × Rr, there are not three white-flowered plants for every red-flowered plant; rather, there is one white-flowered plant for every three red-flowered plants. White flower color is recessive and will only appear in the homozygous recessive condition (rr).
This option is incorrect as well. For all offspring to have white flowers, both parents would need to be homozygous recessive (rr). Since the parents in this cross are heterozygous (Rr), it is impossible for all offspring to express the white phenotype.
This choice is also incorrect. While it might seem plausible that all offspring could be red if both parents were homozygous dominant (RR), the presence of the recessive allele (r) ensures that at least one offspring will express the white flower phenotype. Thus, not all offspring can be red.
The expected phenotypic ratio from the cross of Rr × Rr is 3 red-flowered plants to 1 white-flowered plant, resulting from the combinations of the dominant and recessive alleles. This classic Mendelian inheritance pattern illustrates how dominant traits can overshadow recessive traits in the offspring’s phenotype, leading to a predictable distribution of flower colors in the next generation.
Related Questions
View allWhich of the following types of pathogen is responsible for the common...
Which of the following is a true statement about liquid water?
Which of the following are linked together to form proteins?
A solar eclipse is most likely to occur when
Sweating is a human body's attempt to maintain a constant
Related Quizzes
View allPraxis 5001 Test with Answers
Praxis 5002 Study Guide
5002 Praxis Practice Test
Reading & Language Arts Praxis 5002
Praxis 5002 Reading and Language Arts Exam
Praxis 5003 Exam with Outline
5003 Praxis Math Answers
Praxis 5003 Study Guide
Praxis Social Studies 5004
Praxis 5004 Social Studies
- ✓ 500+ Practice Questions
- ✓ Detailed Explanations
- ✓ Progress Analytics
- ✓ Exam Simulations