Please enable JavaScript.
Coggle requires JavaScript to display documents.
Non-Mendelian Inheritance (Codominance (When both alleles are expressed…
Non-Mendelian Inheritance
Codominance
When both alleles are expressed equally in the phenotype of the heterozygote Ex) A flower with mixed pink and white petals
Incomplete Dominance
Occurs when the phenotype of a heterozygote offspring is somewhere in between the phenotypes of both homozygous parents; a completely dominant allele does not occur. Ex) A flower being pink when the 2 alleles are red pr white flowers
Polygenic Characteristics
Controlled by more than 1 gene and each gene may have two or more alleles
If the genes are located close together on the same chromosome, they are likely to be inherited together. However, it is possible that they will be separated by crossing-over during meiosis, in which case they may be inherited independently of one another.
If the genes are on nonhomologous chromosomes, they may be recombined in various ways because of independent assortment.
Effects of Environment on Phenotype
Environmental factors influence the individual's phenotype, how genes are expressed
Ex) Genes are a major determinant of human skin color. Exposure to ultraviolet radiation can increase the amount of pigment in the skin and make it appear darker.
Ex) Genes play an important part in determining our adult height. However, factors such as poor nutrition can prevent us from achieving our full genetic potential.
Multiple Alleles
Having more than 2 allels
Ex) ABO blood type in humans. There are three common alleles for the gene that controls this characteristic.
Type A blood: IAIA, IAi
Type B blood: IB IB, IB i
Type AB blood: IAIB
Type O blood: ii