* Dominant Genes: These genes express their trait even if only one copy is present. They "mask" the effect of the recessive gene.
* Recessive Genes: These genes only express their trait if two copies are present. They are "masked" by the dominant gene if only one copy is present.
Here's an analogy: Think of a brown-eyed parent and a blue-eyed parent having a child.
* The brown-eyed parent has at least one copy of the brown eye gene (B).
* The blue-eyed parent has two copies of the blue eye gene (b).
The child inherits one gene from each parent. The possible combinations are:
* BB: Brown eyes (dominant gene, brown eyes are expressed)
* Bb: Brown eyes (dominant gene, brown eyes are expressed)
* bb: Blue eyes (recessive gene, blue eyes are expressed)
Key points:
* A dominant gene needs only one copy to be expressed.
* A recessive gene needs two copies to be expressed.
* Both parents can carry recessive genes even if they don't show the trait themselves.
Important Note: Not all traits are controlled by simple dominant-recessive relationships. Some traits are influenced by multiple genes (polygenic inheritance) or interactions between genes (epistasis).
