28) Quantitative population genetics in breeding: features of polygenic traits, QTL Flashcards
Quantitative population genetics
Characterizes population in its polygenic traits using phenotypic performances or genomic information
Analyses the genetic determination and environmental impact on the polygenic trait and measures alteration by time
Quantitative trait
Characteristic trait that can be expressed mathematically
Examples of quantitative traits
- Milk yield
- Racing abilities
- Herding abilities
Quantitative traits are determined by…
Many genes that may be continuous or threshold in nature
Continuous trait
- Quantitative traits with a continuous phenotypic range.
- Often polygenic and may also be influenced significantly by environmental effects.
Quantitative traits are characterised by…
Normal distribution
Phenotypic value (P)
- The combined effect of the genotypic value (G) and the environmental deviation (E)
- P = G + E
Genotypic value (G)
- The combined effect of all the genetic effects
- (nuclear genes, mitochondrial genes and gene interactions)
Additive effect (A)
The cumulative effect of individual genes
Dominance effect (D)
The result of interactions between those genes
Environmental deviation
Environmental component (E) and interaction factor (I), describing the interaction between genes and the environment.
P=
A + D + I + E
The genetic effect can only be determined…
- In entire populations by estimating the variance
- Not by a single individual
Vp =
VA + VD + VI + VE
Secondary quantitative trait
Help to realise the primary trait
