Contents: Learn the definition of monohybrid cross and dihybrid cross. Learn the difference between monohybrid cross and dihybrid cross. Learn the steps involved in monohybrid cross and dihybrid cross. Learn about Punnet square. Learn about monohybrid ratio and dihybrid ratio.

1. Monohybrid Cross &
Dihybrid Cross
ILAKKIYA S

2. Definition of Monohybrid Cross
1 Simple yet
Powerful
Monohybrid cross
involves the breeding
of two individuals that
differ in only one trait.
2 Example
Consider crossing two
pea plants with
different flower colors,
such as purple and
white.
3 Outcome
This cross helps
reveal how traits are
inherited from one
generation to the
next.
Definition of Dihybrid Cross
1 Examining
Multiple Traits
Dihybrid cross involves
the breeding of two
individuals that differ in
two different traits.
2 Example
For example, you
could cross two pea
plants that differ in
both flower color and
plant height.
3 Outcome
This cross helps
determine how
different genes for
different traits are
inherited together.

3. Punnett Square
A Visual Tool
The Punnett square is a graphical
representation used to predict the possible
genotypes and phenotypes of offspring.
Genotype represents the genetic makeup,
while phenotype refers to the physical
expression of a trait.

4. Difference between Monohybrid Cross
and Dihybrid Cross
Monohybrid Cross Dihybrid Cross
Studies one trait Studies two traits
One Punnett square is used Two Punnett squares are used
Produces 3:1 phenotypic ratio Produces 9:3:3:1 phenotypic ratio
Shows the inheritance of one gene Shows the inheritance of two genes
Examples: Seed color, flower color Examples: Seed color and shape, flower
color and height

5. Monohybrid cross

6. Dihybrid cross

7. Monohybrid and Dihybrid Ratios
1 Monohybrid
Produces a phenotypic ratio of 3:1,
with 25% homozygous dominant,
50% heterozygous, and 25%
homozygous recessive offspring.
2
Dihybrid
Produces a phenotypic ratio of
9:3:3:1, where 9/16 show both
dominant traits, 3/16 show one
dominant trait, 3/16 show the other
dominant trait, and 1/16 show both
recessive traits.

8. Conclusion
Monohybrid crosses are a
powerful tool for
understanding the
inheritance of a single trait,
while dihybrid crosses help
unravel the complexities of
two traits.

9. Reference :
https://unacademy.com/content/neet-
ug/study-material/biology/monohybrid-and-
dihybrid/