* Dominant/Recessive Inheritance:
* One allele is dominant, meaning it masks the expression of the recessive allele.
* The phenotype will be determined by the dominant allele, even if the recessive allele is also present.
* Example: Brown eyes (dominant) over blue eyes (recessive). A person with one brown eye allele and one blue eye allele will have brown eyes.
* Incomplete Dominance:
* Neither allele is fully dominant over the other.
* The phenotype is a blend or intermediate between the two homozygous phenotypes.
* Example: Red snapdragons (RR) crossed with white snapdragons (WW) produce pink snapdragons (RW).
* Codominance:
* Both alleles are expressed equally and independently.
* The phenotype shows characteristics of both alleles.
* Example: Blood type AB. Both A and B alleles are expressed, resulting in a unique blood type different from A or B alone.
* Polygenic Inheritance:
* Multiple genes contribute to a single trait.
* The phenotype is determined by the combined effects of all these genes.
* Example: Height, skin color, eye color. The wide range of these traits is due to the interaction of numerous genes.
It's important to note that the interaction between alleles is not always simple and can be influenced by factors like environmental conditions. For example, the expression of genes related to height can be influenced by nutrition and other environmental factors.
