Dihybrid Crosses

Dihybrid Crosses

• 2 traits are changed

• complex 4 X 4 Punnett Square

​Dihybrid

• only 1 trait is changed

• simple 2 X 2 Punnett Square

​Monohybrid

How is Dihybrid crosses different from Monohybrid crosses?

​Dihybrid Cross

• cross between plants/organisms involving 2 different traits

• di = 2

• Mendel discovered that genes for different traits pass independently of each other

• Recombine 4 (dihybrid) ways instead of 2 (monohybrid)

  • EX: H = hairy h = hairless S = likes sinks s = doesn't like sinks

  • Possible combinations:

    • Hairy & likes sinks

    • Hairy & doesn't like sinks

    • Hairless & likes sinks

    • Hairless & doesn't like sinks

FOIL Method

F - First
O - Outside
I - Inside
L - Last

​TtFf x Ttff

​	​	​	​
​	​	​	​
​	​	​	​
​	​	​	​

​TF

​Tf

​​Tf

​​​Tf

​tF

​tf

​tf

​tf

​Genotypes:

TTFf

TTff

TtFf

Ttff

ttFf

ttff

​Phenotypes:


Tall w/freckles

Tall w/out freckles

Short w/freckles

Short w/out freckles