Textbook Question
Discuss how Mendel's monohybrid results served as the basis for all but one of his postulates. Which postulate was not based on these results? Why?
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Ch. 3 - Mendelian Genetics
Klug12th EditionConcepts of Genetics ISBN: 9780135564776
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Table of contents
- Ch. 1 - Introduction to Genetics17
- Ch. 2 - Mitosis and Meiosis36
- Ch. 3 - Mendelian Genetics51
- Ch. 4 - Extensions of Mendelian Genetics74
- Ch. 5 - Chromosome Mapping in Eukaryotes51
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages46
- Ch. 7 - Sex Determination and Sex Chromosomes33
- Ch. 8 - Chromosome Mutations: Variation in Number and Arrangement40
- Ch. 9 - Extranuclear Inheritance31
- Ch. 10 - DNA Structure and Analysis43
- Ch. 11 - DNA Replication and Recombination44
- Ch. 12 - DNA Organization in Chromosomes30
- Ch. 13 - The Genetic Code and Transcription54
- Ch. 14 - Translation and Proteins47
- Ch. 15 - Gene Mutation, DNA Repair, and Transposition41
- Ch. 16 - Regulation of Gene Expression in Bacteria29
- Ch. 17 - Transcriptional Regulation in Eukaryotes41
- Ch. 18 - Post-transcriptional Regulation in Eukaryotes33
- Ch. 19 - Epigenetics33
- Ch. 20 - Recombinant DNA Technology44
- Ch. 21 - Genomic Analysis36
- Ch. 22 - Applications of Genetic Engineering and Biotechnology36
- Ch. 23 - Developmental Genetics37
- Ch. 24 - Cancer Genetics34
- Ch. 25 - Quantitative Genetics and Multifactorial Traits54
- Ch. 26 - Population and Evolutionary Genetics45
Chapter 3, Problem 8
Based on the preceding cross, what is the probability that an organism in the F₂ generation will have round seeds and green cotyledons and be true breeding?
Verified step by step guidance1
insert step 1> Identify the genotypes of the parent organisms in the initial cross (P generation) and determine the alleles involved for seed shape and cotyledon color.
insert step 2> Determine the F₁ generation genotype by performing a Punnett square cross of the P generation. Note that the F₁ generation is typically heterozygous for both traits if the P generation was homozygous.
insert step 3> Set up a dihybrid cross for the F₁ generation to predict the F₂ generation. Use a 4x4 Punnett square to account for all possible combinations of alleles for the two traits.
insert step 4> Identify the phenotype of interest: round seeds and green cotyledons. Determine which genotype(s) correspond to this phenotype.
insert step 5> Calculate the probability of the organism being true breeding for both traits by identifying the homozygous genotype(s) that result in the desired phenotype.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Mendelian Genetics
Mendelian genetics is the study of how traits are inherited through generations, based on the principles established by Gregor Mendel. It involves understanding dominant and recessive alleles, genotype, and phenotype. In this context, the inheritance patterns of traits like seed shape and cotyledon color are analyzed to predict probabilities in offspring.
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03:45
Descriptive Genetics
True Breeding
True breeding refers to organisms that, when self-fertilized, produce offspring that are identical to themselves for specific traits. This means that the organism is homozygous for the traits in question. In the context of the question, determining if the F₂ generation is true breeding for round seeds and green cotyledons requires understanding the genetic makeup of the parents and the resulting offspring.
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18:27Chi Square Analysis
Punnett Square
A Punnett square is a diagram used to predict the genetic makeup of offspring from a cross between two organisms. It helps visualize the combinations of alleles that can result from the mating of parent organisms. By using a Punnett square, one can calculate the probability of specific traits, such as round seeds and green cotyledons, appearing in the F₂ generation.
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Related Practice
Textbook Question
What advantages were provided by Mendel's choice of the garden pea in his experiments?
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Textbook Question
Mendel crossed peas having round seeds and yellow cotyledons (seed leaves) with peas having wrinkled seeds and green cotyledons. All the F₁ plants had round seeds with yellow cotyledons. Diagram this cross through the F₂ generation, using both the Punnett square and forked-line, or branch diagram, methods.
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Textbook Question
Which of Mendel's postulates can only be demonstrated in crosses involving at least two pairs of traits? State the postulate.
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Textbook Question
In a cross between a black and a white guinea pig, all members of the F₁ generation are black. The F₂ generation is made up of approximately 3/4 black and 1/4 white guinea pigs. Diagram this cross, showing the genotypes and phenotypes.
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Textbook Question
In a cross between a black and a white guinea pig, all members of the F₁ generation are black. The F₂ generation is made up of approximately 3/4 black and 1/4 white guinea pigs. What will the offspring be like if two F₂ white guinea pigs are mated?
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