Science Common Sense

1020 - What is the difference between a dominant gene and a recessive gene?

Imagine you have two copies of a gene, one from mom and one from dad. These genes can be either dominant (D) or recessive (d).

• A dominant gene (D) is strong and will always show its trait, even if you have just one copy of it.
• A recessive gene (d) is weak and will only show its trait if you have two copies of it (dd). If you have one dominant and one recessive gene (Dd), the dominant gene will cover up the recessive gene.

For example, let's say brown eyes (D) are dominant and blue eyes (d) are recessive. If you have one brown eye gene (D) and one blue eye gene (d), you will still have brown eyes because the brown eye gene is stronger.