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Ch. 19 - Genetic Analysis of Quantitative Traits
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Sanders 3rd EditionCh. 19 - Genetic Analysis of Quantitative Traits문제 10f
19장, 문제 10f

Three pairs of genes with two alleles each (A₁ and A₂, B₁ and B₂, and C₁ and C₂) control the height of a plant. The alleles of these genes have an additive relationship: Each copy of alleles A₁, B₁, and C₁ contributes 6 cm to plant height, and each copy of alleles A₂, B₂, and C₂ contributes 3 cm. Identify the number of different phenotypes (expected plant heights) that are possible with these three genes.

검증된 단계별 안내
1
Step 1: Understand the problem. The plant's height is determined by three pairs of genes (A, B, and C), each with two alleles. The alleles contribute additively to the height: A₁, B₁, and C₁ contribute 6 cm each, while A₂, B₂, and C₂ contribute 3 cm each. We need to calculate the number of distinct phenotypes (heights) possible.
Step 2: Determine the total number of alleles contributing to the phenotype. Each gene pair (A, B, C) has two alleles, and there are three gene pairs. This means there are 6 total alleles (2 alleles per gene × 3 genes).
Step 3: Calculate the range of contributions to the phenotype. Each allele contributes either 6 cm (A₁, B₁, C₁) or 3 cm (A₂, B₂, C₂). The maximum contribution occurs when all 6 alleles are of the 6 cm type (6 × 6 = 36 cm), and the minimum contribution occurs when all 6 alleles are of the 3 cm type (6 × 3 = 18 cm).
Step 4: Determine the possible combinations of allele contributions. The total contribution to height depends on the number of 6 cm alleles (x) and 3 cm alleles (6 - x). The total height is given by the formula: \( \text{Height} = 6x + 3(6 - x) \). Simplify this to \( \text{Height} = 3x + 18 \), where x ranges from 0 to 6 (the number of 6 cm alleles).
Step 5: Calculate the number of distinct phenotypes. Since x can take on integer values from 0 to 6, there are 7 possible values for x. Each value of x corresponds to a unique height, meaning there are 7 distinct phenotypes (heights) possible.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Alleles and Genotypes

Alleles are different versions of a gene that can exist at a specific locus on a chromosome. In this scenario, each gene (A, B, C) has two alleles (A₁/A₂, B₁/B₂, C₁/C₂). The combination of alleles inherited from both parents forms the genotype, which ultimately influences the phenotype, or observable traits, such as plant height.
추천 영상:
가이드 코스
03:03
New Alleles and Migration

Additive Gene Interaction

Additive gene interaction occurs when the effects of different alleles contribute cumulatively to a trait. In this case, each allele contributes a specific height increment to the plant. For example, A₁ contributes 6 cm, while A₂ contributes 3 cm, leading to a total height that is the sum of contributions from all alleles present in the genotype.
추천 영상:
가이드 코스
07:56
Interacting Genes Overview

Phenotypic Variation

Phenotypic variation refers to the observable differences in traits among individuals, which can arise from genetic differences and environmental influences. In this question, the phenotypes are the different possible heights of the plants, determined by the combinations of alleles from the three genes, leading to a range of potential plant heights based on the additive contributions of each allele.
추천 영상:
가이드 코스
09:28
Genomic Variation
관련 실천
교과서 질문

Three pairs of genes with two alleles each (A₁ and A₂, B₁ and B₂, and C₁ and C₂) control the height of a plant. The alleles of these genes have an additive relationship: Each copy of alleles A₁, B₁, and C₁ contributes 6 cm to plant height, and each copy of alleles A₂, B₂, and C₂ contributes 3 cm. Identify the number of different genotypes that are possible with these three genes.

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교과서 질문

Three pairs of genes with two alleles each (A₁ and A₂, B₁ and B₂, and C₁ and C₂) control the height of a plant. The alleles of these genes have an additive relationship: Each copy of alleles A₁, B₁, and C₁ contributes 6 cm to plant height, and each copy of alleles A₂, B₂, and C₂ contributes 3 cm. What is the expected height of a plant with the genotype A₁A₂B₂B₂C₁C₂?

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교과서 질문

Two inbred lines of sunflowers (P₁ and P₂) produce different total weights of seeds per flower head. The mean weight of seeds (grams) and the variance of seed weights in different generations are as follows:

Use the information above to determine VG, VE, and VP for this trait.


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교과서 질문

In selective breeding experiments, it is frequently observed that the strains respond to artificial selection for many generations, with the selected phenotype changing in the desired direction. Often, however, the response to artificial selection reaches a plateau after many generations, and the phenotype no longer changes as it did in past generations. Once a plateau has been reached, is the heritability of the trait very high or is it very low? Explain.

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교과서 질문

In selective breeding experiments, it is frequently observed that the strains respond to artificial selection for many generations, with the selected phenotype changing in the desired direction. Often, however, the response to artificial selection reaches a plateau after many generations, and the phenotype no longer changes as it did in past generations. What is the genetic explanation for the plateau phenomenon?

609
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교과서 질문

Three pairs of genes with two alleles each (A₁ and A₂, B₁ and B₂, and C₁ and C₂) control the height of a plant. The alleles of these genes have an additive relationship: Each copy of alleles A₁, B₁, and C₁ contributes 6 cm to plant height, and each copy of alleles A₂, B₂, and C₂ contributes 3 cm. Identify all possible genotypes for plants with an expected height of 33 cm.

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