Skip to main content
Ch. 25 - Quantitative Genetics and Multifactorial Traits
Klug - Concepts of Genetics 12th Edition
Klug12th EditionConcepts of GeneticsISBN: 9780135564776Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoKlug 12th EditionCh. 25 - Quantitative Genetics and Multifactorial TraitsProblema 12a
Capitolo 25, Problema 12a

The following variances were calculated for two traits in a herd of hogs.
Table showing phenotypic, genetic, and additive variances for back fat and body length traits in a hog herd.
Calculate broad-sense (H²) and narrow-sense (h²) heritabilities for each trait in this herd.

Guida verificata passo dopo passo
1
Identify the variances given for each trait: phenotypic variance (\(V_P\)), genetic variance (\(V_G\)), and additive genetic variance (\(V_A\)). These are provided in the table for back fat and body length.
Recall the formula for broad-sense heritability (\(H^2\)), which is the proportion of phenotypic variance due to total genetic variance: \(H^2 = \frac{V_G}{V_P}\)
Recall the formula for narrow-sense heritability (\(h^2\)), which is the proportion of phenotypic variance due to additive genetic variance: \(h^2 = \frac{V_A}{V_P}\)
For each trait (back fat and body length), substitute the values from the table into the formulas for \(H^2\) and \(h^2\) to set up the calculations.
Interpret the heritability values to understand the genetic contribution to the traits: higher values indicate a greater genetic influence on the phenotypic variation.

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:
2m

Concetti chiave

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

Phenotypic Variance (V_P)

Phenotypic variance represents the total variation observed in a trait within a population. It includes genetic variance, environmental variance, and their interactions. Understanding V_P is essential because it forms the denominator in heritability calculations, reflecting all sources of trait variation.
Video consigliato:
Percorso guidato
08:34
Analyzing Trait Variance

Genetic Variance (V_G) and Additive Genetic Variance (V_A)

Genetic variance (V_G) is the portion of phenotypic variance due to genetic differences among individuals. Additive genetic variance (V_A) is the part of V_G attributable to the additive effects of alleles, which predictably pass from parents to offspring. V_A is crucial for narrow-sense heritability, while V_G is used for broad-sense heritability.
Video consigliato:
Percorso guidato
13:40
Traits and Variance

Broad-sense (H²) and Narrow-sense (h²) Heritability

Broad-sense heritability (H²) is the ratio of total genetic variance (V_G) to phenotypic variance (V_P), indicating the proportion of trait variation due to all genetic factors. Narrow-sense heritability (h²) is the ratio of additive genetic variance (V_A) to V_P, reflecting the proportion of variation that can be passed to offspring and is key for predicting response to selection.
Video consigliato:
Percorso guidato
07:04
Calculating Heritability
Pratica correlata
Domanda del libro di testo

The mean and variance of plant height of two highly inbred strains (P₁ and P₂) and their progeny (F₁ and F₂) are shown here.


  Strain  Mean (cm)  Variance 

   P₁     34.2        4.2

   P₂     55.3        3.8

   F₁     44.2        5.6

   F₂     46.3       10.3


Calculate the broad-sense heritability (H²) of plant height in this species.

814
views
Domanda del libro di testo

List as many human traits as you can that are likely to be under the control of a polygenic mode of inheritance.

462
views
Domanda del libro di testo

What kind of heritability estimates (broad sense or narrow sense) are obtained from human twin studies?

1192
views
Domanda del libro di testo

The following variances were calculated for two traits in a herd of hogs.

Which of the two traits will respond best to selection by a breeder? Why?

559
views
Domanda del libro di testo

Corn plants from a test plot are measured, and the distribution of heights at 10-cm intervals is recorded in the following table: 

 Height (cm)   Plants (no.)    

100          20    

110          60    

120          90    

130         130    

140         180   

 150         120    

160          70    

170         50    

180         40 

Calculate 

(a) the mean height, 

(b) the variance, 

(c) the standard deviation, and 

(d) the standard error of the mean. 

Plot a rough graph of plant height against frequency. Do the values represent a normal distribution? Based on your calculations, how would you assess the variation within this population?

941
views
Domanda del libro di testo

A hypothetical study investigated the vitamin A content and the cholesterol content of eggs from a large population of chickens. The following variances (V) were calculated.

Calculate the narrow-sense heritability (h²) for both traits.

475
views