Skip to main content
Ch. 4 - Modification of Mendelian Ratios
Klug - Essentials of Genetics 10th Edition
Klug10th EditionEssentials of GeneticsISBN: 9780135588789Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoKlug 10th EditionCh. 4 - Modification of Mendelian RatiosProblema 9a
Capitolo 4, Problema 9a

Given the inheritance pattern of coat color in rats described in Problem 17, predict the genotype and phenotype of the parents who produced the following offspring:
9/16 gray: 3/16 yellow: 3/16 black: 1/16 cream

Guida verificata passo dopo passo
1
Identify the inheritance pattern described in Problem 17, which likely involves two genes with epistatic interactions affecting coat color in rats. Typically, such ratios suggest a dihybrid cross with epistasis.
Assign symbols to the genes involved. For example, let gene A control pigment production (A = pigment, a = no pigment) and gene B control pigment color (B = black, b = yellow). The cream phenotype might result from a double recessive or interaction between these genes.
Write down the expected phenotypic ratios for a dihybrid cross with epistasis. The given offspring ratio (9/16 gray, 3/16 yellow, 3/16 black, 1/16 cream) suggests a 9:3:3:1 ratio, typical of independent assortment without epistasis, but with different phenotypes assigned to each genotype combination.
Determine the genotypes corresponding to each phenotype based on the gene symbols. For example, gray might be A_B_, yellow A_bb, black aaB_, and cream aabb. This helps to map phenotypes to genotypes.
Use the offspring phenotypic ratio to infer the parental genotypes. Since the ratio matches a 9:3:3:1 ratio, the parents are likely heterozygous for both genes (AaBb x AaBb). Confirm this by setting up a Punnett square and verifying the offspring ratios.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
1m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Mendelian Inheritance and Dihybrid Crosses

Mendelian inheritance explains how traits are passed from parents to offspring through dominant and recessive alleles. A dihybrid cross involves two genes, each with two alleles, producing a 9:3:3:1 phenotypic ratio in the F2 generation when both parents are heterozygous for both traits.
Video consigliato:
Percorso guidato
15:24
Punnet Square

Epistasis and Coat Color Genetics

Epistasis occurs when one gene masks or modifies the expression of another gene. In coat color genetics, interactions between multiple genes can produce complex phenotypic ratios different from classic Mendelian ratios, such as the presence of cream or yellow colors influenced by gene interactions.
Video consigliato:
Percorso guidato
13:08
Epistatic Genes

Genotype to Phenotype Prediction

Predicting genotype and phenotype involves using observed offspring ratios to infer parental genotypes. By comparing expected Mendelian ratios to observed data, one can deduce which alleles parents carry and how they combine to produce specific phenotypes in offspring.
Video consigliato:
Percorso guidato
07:52
Gamete Genotypes
Pratica correlata
Domanda del libro di testo

Flower color may be red, white, or pink, and flower shape may be personate or peloric. For the following crosses, determine the P₁ and F₁ genotypes:

550
views
Domanda del libro di testo

Given the inheritance pattern of coat color in rats described in Problem 17, predict the genotype and phenotype of the parents who produced the following offspring: 27/64 gray:

16/64 albino: 9/64 yellow: 9/64 black: 3/64 cream

457
views
Domanda del libro di testo

Given the inheritance pattern of coat color in rats described in Problem 17, predict the genotype and phenotype of the parents who produced the following offspring:

9/16 gray: 3/16 yellow: 4/16 albino

561
views
Domanda del libro di testo

In rats, the following genotypes of two independently assorting autosomal genes determine coat color:

A third gene pair on a separate autosome determines whether or not any color will be produced. The CC and Cc genotypes allow color according to the expression of the A and B alleles. However, the cc genotype results in albino rats regardless of the A and B alleles present. Determine the F₁ phenotypic ratio of the following crosses:

AAbbCC×aaBBcc

595
views
Domanda del libro di testo

In rats, the following genotypes of two independently assorting autosomal genes determine coat color:

A third gene pair on a separate autosome determines whether or not any color will be produced. The CC and Cc genotypes allow color according to the expression of the A and B alleles. However, the cc genotype results in albino rats regardless of the A and B alleles present. Determine the F₁ phenotypic ratio of the following crosses:

AaBbCc×AaBbcc

474
views
Domanda del libro di testo

A husband and wife have normal vision, although both of their fathers are red–green color-blind, an inherited X-linked recessive condition. What is the probability that their first child will be (a) a normal son, (b) a normal daughter, (c) a color-blind son, (d) a color-blind daughter?

865
views
1
rank