Textbook Question
Compare and contrast the following terms:
Monohybrid cross and Test cross
Ch. 2 - Transmission Genetics
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 2, Problem 3
For the cross Aabb × aaBb, what is the expected genotype ratio? What is the expected phenotype ratio?
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Identify the genotypes of the parents: Parent 1 is Aabb and Parent 2 is aaBb. Each parent can produce gametes based on the alleles they carry for each gene.
Determine the possible gametes from each parent. For Aabb, the possible gametes are A b (since the genotype is A b b, the alleles for the two genes are A or a and b or B). For aaBb, the possible gametes are a B and a b.
Set up a Punnett square using the gametes from each parent. The rows represent the gametes from Parent 1 (A b), and the columns represent the gametes from Parent 2 (a B and a b). Fill in the squares by combining the alleles from each gamete.
Write out the genotypes from the Punnett square and count the frequency of each genotype to determine the genotype ratio. Remember that each genotype consists of two alleles for each gene, for example, AaBb, Aabb, aaBb, or aabb.
Determine the phenotype ratio by considering the dominance relationships of the alleles. Typically, uppercase letters represent dominant alleles and lowercase letters represent recessive alleles. Identify which genotypes correspond to which phenotypes based on dominance, then count the frequency of each phenotype.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Dihybrid Cross and Genotype Combinations
A dihybrid cross involves two genes, each with two alleles. To find genotype ratios, list all possible allele combinations from each parent and determine offspring genotypes by combining these alleles. This helps predict the frequency of each genotype in the progeny.
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07:52
Gamete Genotypes
Mendelian Inheritance and Independent Assortment
Mendel's law of independent assortment states that alleles of different genes segregate independently during gamete formation. This principle allows the prediction of genotype and phenotype ratios by treating each gene's inheritance separately and then combining the results.
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04:58Gamete Genetics and Independent Assortment
Phenotype Determination from Genotype
Phenotypes depend on dominant and recessive allele interactions. Dominant alleles mask recessive ones, so the phenotype ratio is derived by grouping genotypes based on dominant or recessive trait expression, enabling prediction of observable traits in offspring.
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07:52Gamete Genotypes
Related Practice
Textbook Question
Compare and contrast the following terms:
Dihybrid cross and Trihybrid cross
Textbook Question
For the cross BB×Bb, what is the expected genotype ratio? What is the expected phenotype ratio?
Textbook Question
In mice, black coat color is dominant to white coat color. In the pedigree shown here, mice with a black coat are represented by darkened symbols, and those with white coats are shown as open symbols. Using allele symbols B and b, determine the genotypes for each mouse.
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Textbook Question
A man, J.B., has a sister with autosomal recessive galactosemia (OMIM 230400), and his partner, S.B., has a brother with galactosemia. Galactosemia is a serious condition caused by an enzyme deficiency that prevents the metabolism of the sugar galactose. Neither J.B. nor S.B. has galactosemia, but they are concerned about the risk that a future child of theirs will have the condition. What is the probability their first child will have galactosemia?
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Textbook Question
Two parents plan to have three children. What is the probability that the children will be two girls and one boy?