When we explore genetics, especially Mendelian genetics, one of the best tools we have is something called the Punnett square.

Think of it as a simple grid that helps us figure out the genetic traits of babies from two parents. Understanding how dominant and recessive traits work in these squares is really important.

Let's break it down:

Dominant traits are the ones that appear even if there is just one copy of that trait. We usually show a dominant trait with a capital letter.

For example, if we’re talking about flower colors, purple would be a dominant trait and written as “P”.

On the other hand, recessive traits only show up when both copies are the recessive trait. We represent this with a lowercase letter. So, for the flower example, white flowers would be written as “p”.

Now, how do we use a Punnett square?

Start by writing the alleles (the different versions of the traits) from the parents at the top and on the sides of the square.

Let’s say we have one parent who has two dominant purple traits (PP) and another parent with two recessive white traits (pp). Your Punnett square would look like this:

    P   P
  ---------
p | Pp | Pp |
  ---------
p | Pp | Pp |
  ---------

From this grid, we can see that all the offspring (100%) will have the genotype “Pp”. This means they will all show the dominant purple trait!

Now, if we mix two parents that are both “Pp” (heterozygous), the results are different. You would get a classic ratio of 1:2:1 for the genotypes. This means about 75% of the offspring will show the purple trait, while around 25% will have the white trait.

Learning how to use these traits in the Punnett square gives you a great way to predict genetic outcomes!