Now we understand what we mean by phenotypic variation, we can move on to answering the question. Two things contribute to variation in phenotype – variation in genotype, and variation in environment. First let’s deal with variation in genotype. A genotype is the genetic information of an organism.
What are the two main factors responsible for phenotypic variation?
Two types of factors are recognized as contributing to the phenotypic variation in a population, genetic and environmental.
What are the components of phenotypic variance?
Phenotypic variance, usually combines the genotype variance with the environmental variance. Genetic variance has three major components: the additive genetic variance, dominance variance, and epistatic variance.
What are two things that determine your phenotype?
The term “phenotype” refers to the observable physical properties of an organism; these include the organism’s appearance, development, and behavior. An organism’s phenotype is determined by its genotype, which is the set of genes the organism carries, as well as by environmental influences upon these genes.
What are the factors that affect variation?
Many factors can contribute to growth variation across and among populations such as genetic factors, nutrition, environmental conditions, social conditions, and cultural conditions. Genetic Factors: Genotype can have a strong effect on growth as shown in the next two examples.
Why are polymorphisms so important to phenotypic variation?
It is a special aspect of genetic variation because it connotes segregation of relatively common variants within populations and also implies the presence of some evolutionary mechanism(s) for their maintenance.
What is the difference between phenotypic and genotypic variation?
Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).
How do you find phenotypic variation?
Variance Components of a Quantitative Trait
- VP = VG + VE + VGE VP = total phenotypic variation of the segregating population. …
- VG = VA + VD + VI and the total phenotypic variance can be rewritten as.
- VP = VA + VD + VI + VE + VGE …
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Is all phenotypic variation the result of genotypic variation?
All phenotypic variation is the result of genotypic variation. All nucleotide variability results in neutral variation. All new alleles are the result of nucleotide variability. … The frequency of the strong-beak alleles increased in each bird as the drought persisted.
What are the three main sources of genetic variation?
For a given population, there are three sources of variation: mutation, recombination, and immigration of genes. However, recombination by itself does not produce variation unless alleles are segregating already at different loci; otherwise there is nothing to recombine.
What does epistasis influence?
More important, epistasis makes the marginal (that is, additive) effects of alleles depend on the current genetic background. Thus, even though the immediate response of allele frequencies to selection is due to the additive component of genetic variance, these additive effects may change over time.