Does genetic variation cause phenotypic variation?
Variation allows some individuals within a population to adapt to the changing environment. Because natural selection acts directly only on phenotypes, more genetic variation within a population usually enables more phenotypic variation.
What are the results of genetic variation?
Genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism’s offspring).
Is all phenotypic variation heritable?
The first rule of any reconstruction or prediction of evolution is that the phenotypic variation must be heritable. … It should not be supposed that all variable traits are heritable. Certain metabolic traits (such as resistance to high salt concentrations in Drosophila) show individual variation but no heritability.
How does phenotype depend on genotype?
The phenotype is the visible or expressed trait, such as hair color. The phenotype depends upon the genotype but can also be influenced by environmental factors.
|Inheritance||Partly inherited by offspring, as one of the two alleles is passed on during reproduction.||Cannot be inherited.|
What are the differences between genotypes and phenotypes?
Genotype versus phenotype. An organism’s genotype is the set of genes that it carries. An organism’s phenotype is all of its observable characteristics — which are influenced both by its genotype and by the environment. … For example, differences in the genotypes can produce different phenotypes.
Which type of selection leads to increased phenotypic and genetic variation?
In directional selection, a population’s genetic variance shifts toward a new phenotype when exposed to environmental changes. Diversifying or disruptive selection increases genetic variance when natural selection selects for two or more extreme phenotypes that each have specific advantages.
How can variation within a DNA sequence produce different phenotypes?
Phenotypic variation occurs when the expression of genes is changed in response to the environment, for instance by the induction or repression of synthesis of particular enzymes.
What are the 3 types 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.