Key Concepts:
* Genes: Segments of DNA that carry the instructions for building and maintaining an organism.
* Alleles: Different versions of the same gene. For example, there are alleles for blue eyes and brown eyes.
* Dominant Allele: An allele that masks the effect of a recessive allele. It will be expressed even if only one copy is present.
* Recessive Allele: An allele that is only expressed when two copies are present.
How Recessive Genes Work:
* One Copy: If you inherit one copy of a recessive gene and one copy of a dominant gene, the dominant gene will be expressed, and you won't show the recessive trait.
* Two Copies: Only if you inherit two copies of the recessive gene will the trait be expressed.
Example:
* Eye Color: Let's say brown eyes (B) are dominant and blue eyes (b) are recessive.
* BB: Brown eyes (two dominant alleles)
* Bb: Brown eyes (one dominant and one recessive allele)
* bb: Blue eyes (two recessive alleles)
Characteristics of Recessive Genes:
* Can "Skip Generations": Recessive traits can appear in a child even if neither parent has the trait because each parent can carry the recessive allele without expressing it.
* Often Associated with Genetic Disorders: Many genetic disorders are caused by recessive genes. This is because the dominant allele often provides a functional protein, while the recessive allele may be non-functional.
Important Note: The terms "dominant" and "recessive" are relative to each other. One gene can be dominant to another, but recessive to a third gene.
