Mendel bred a purple-flowered pea plant with a white-flowered pea plant and found that all the offspring had purple flowers. But then when he bred together two of the purple-flowered offspring, some of their offspring had white flowers.Using the concepts of dominant and recessive alleles, explain how the trait of white flowers skipped a generation.
Question
Mendel bred a purple-flowered pea plant with a white-flowered pea plant and found that all the offspring had purple flowers. But then when he bred together two of the purple-flowered offspring, some of their offspring had white flowers.Using the concepts of dominant and recessive alleles, explain how the trait of white flowers skipped a generation.
Solution
Mendel's experiments with pea plants laid the foundation for our understanding of genetics, including the concepts of dominant and recessive alleles. Here's how these concepts explain the scenario you described:
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Each organism has two alleles for each trait, one from each parent. These alleles can be either dominant or recessive. In pea plants, the allele for purple flowers is dominant, while the allele for white flowers is recessive.
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When Mendel bred a purple-flowered pea plant (PP) with a white-flowered pea plant (pp), the first generation of offspring all had one dominant (P) and one recessive (p) allele, making them all purple-flowered (Pp). This is because the dominant allele (P) masks the presence of the recessive allele (p).
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However, when Mendel bred two of these purple-flowered offspring (Pp) together, their offspring could inherit any combination of their parents' alleles. This is where the concept of Punnett squares comes in handy. A Punnett square for this cross would look like this:
| P | p ---|---|--- P | PP | Pp p | Pp | pp
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As you can see, there's a 25% chance that an offspring will inherit two recessive alleles (pp) and therefore have white flowers. This is why some of the second-generation offspring had white flowers, even though both of their parents had purple flowers. The trait didn't really "skip" a generation; it was just "hidden" in the first generation by the dominant purple-flower allele.
Similar Questions
Mendel described the parents he crossed to make his first generation of pea plants as being pure for each trait. Today we use the term homozygous instead of pure.Mendel’s first-generation pea plants with purple flowers had which set of alleles?A.Two alleles for purple flowersB.Two alleles for white flowersC.One allele for purple flowers and one allele for white flowersD.The alleles for flowers and the alleles for color
Sometimes, when Mendel crossed two pea plants with each other, he obtained a phenotypic ratio of 3:1 purple-flowered pea plants to white-flowered pea plants. These results are consistent with which set of parents?Multiple ChoiceHomozygous purple pea plant and homozygous white pea plantHeterozygous purple pea plant and homozygous purple pea plantHeterozygous purple pea plant and homozygous white pea plantHeterozygous purple pea plant and heterozygous purple pea plant
Another trait in pea plants that follows a simple inheritance pattern is flower colour. Purple flowers are a dominant trait while white flowers are a recessive trait.Explain what this difference means in terms of the alleles for flower colour.
One of the reasons that Mendel was able to discover the basic principles of genetics using pea plants is because pea plantsMultiple choice question.produce only a small amount of offspring each generation.develop slowly.exhibit traits in forms that are blended and that differ from either parental trait.self-fertilize and cross-fertilize.
In 1866, Mendel published three main conclusions to his findings. Which of the following ideas was not proposed by Mendel?Characteristics are determined by hereditary unitsHereditary units are organised in chromosomesHereditary units can be dominant or recessive Hereditary units are passed on unchanged by both parents3The height of Mendel’s pea plants is controlled by a single gene with two alleles: a dominant tall allele (T) and a recessive short allele (t). In a series of F1 crosses involving one homozygous tall plant (TT) and one short plant (tt), 400 F2 offspring were produced. Approximately how many of these offspring would you expect to be short?200Zero4001004In a series of crosses involving pea plants heterozygous for the height gene, 800 offspring are produced. Approximately how many of these offspring would you expect to be tall?8002006004005Mendel’s investigations were ‘reproducible’. What is meant by this term?The pea plants could be reproducedThe investigations could be repeated by different researchers with different resultsMendel reproduced his own investigations with the same results on numerous occasionsThe investigations could be repeated by different researchers with the same results
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