Here's a breakdown of how alleles relate to dominant and recessive traits:
* Dominant Allele: This allele's trait will always be expressed if present. It is represented by an uppercase letter, such as "B".
* Recessive Allele: This allele's trait will only be expressed if two copies of the recessive allele are present. It is represented by a lowercase letter, such as "b".
Here's an example:
* Gene: Eye color
* Dominant Allele (B): Brown eyes
* Recessive Allele (b): Blue eyes
Possible combinations:
* BB: Brown eyes (dominant allele present)
* Bb: Brown eyes (dominant allele present)
* bb: Blue eyes (two copies of the recessive allele)
Key Points:
* Every individual inherits two alleles for each gene, one from each parent.
* Dominant alleles "mask" the effects of recessive alleles when they are present together.
* Recessive alleles can only express their trait if two copies are present.
It's important to note:
* Not all traits are strictly dominant or recessive. Some traits show incomplete dominance, where the heterozygous genotype results in a phenotype that is a blend of the two alleles.
* Other traits are co-dominant, where both alleles are expressed equally in the heterozygous genotype.
* Many traits are influenced by multiple genes, making the inheritance patterns more complex.
