When we talk about dominant and recessive alleles, think of it like a sports team where different players have different jobs. Let’s make it simple!

Dominant Alleles

• Dominant alleles are like the star players on a team. If they’re around, they usually hide the effects of the recessive alleles.
• For example, in pea plants, the allele for purple flowers (P) is dominant over the allele for white flowers (p). So, if a plant has either $PP$ or $Pp$, it will have purple flowers.

Recessive Alleles

• Recessive alleles are like the supportive team members. They only show their traits when they are paired with another recessive allele.
• In our pea plant example, white flowers only show up in plants with the genotype $pp$.

Genotypes and Phenotypes

• The genotype is like the genetic code (like $PP$, $Pp$, or $pp$). The phenotype is what you can actually see, like purple or white flowers.
• If you cross a plant with genotype $Pp$ (purple) with another $Pp$, the possible genotypes for the baby plants are:
  • $PP$ (purple)
  • $Pp$ (purple)
  • $Pp$ (purple)
  • $pp$ (white)

Ratios in Offspring

• From this cross, we expect a ratio of 3 purple flowers to 1 white flower. This means purple flowers will usually be more common.

In short, dominant and recessive alleles work together to create a lot of different traits based on how they mix. It’s fascinating how the genetics behind these traits affects the world around us!