A Punnett square is a diagram used to predict the genetic outcomes of a breeding experiment, named after Reginald C. Punnett. It allows biologists to determine the probability of offspring having specific genotypes, examining single or multiple traits. The process involves determining alleles from each parent and mapping them in a square to visualize potential genetic combinations.

1. Punnett Square

2. Punnett Square
It is a diagram that is used to
predict an outcome of a
particular cross or breeding
experiment
Named after Reginald C.
Punnett

3. Punnett Square
It is used by biologists to
determine the probability of an
offspring having a
particular genotype.
These tables can be used to
examine the genotypic outcome
probabilities of the offspring of a
single trait (allele), or when
crossing multiple traits from the

4. Punnett Square
Vocabulary
Dominant Genes – Upper Case
(A)
Recessive Genes – Lower Case
(a)
Each parent has two genes for
a trait (Aa), (aa), or (AA)
There can be four possible
combinations for each cross

5. Punnett Square
Vocabulary
Genotype – The gene combination
 Homozygous – Pure dominance or pure
recessive
 Heterozygous – Hybrid mixed
Phenotype – The physical appearance
 Dominant trait
 Recessive trait
 Combination of two traits (Incomplete
dominance)

6. Monohybrid Cross
 Crossing with only one trait
 It is a cross between 2 parents
possessing a pair of contrasting
characters is also known as
monohybrid cross

7. Punnett Square
Process:
1. Determine alleles of
each parent, these
are given as TT,
and tt respectively.
2. Take each
possible allele of
each parent,
separate them, and
place each allele
either along the top,
or along the side of

8. Punnett Square
Process:
Lastly, write the letter
for each allele
across each column
or down each row.
The resultant mix is
the genotype for the
offspring. In this
case, each offspring
has a Tt
(heterozygous tall)
genotype, and
simply a "Tall"

9. Dihybrid Cross
 It is a cross between two different
independent alleles
 The process in doing the Punnett
Square is very similar to the
Monohybrid Cross