Dihybrid Crosses
Dihybrid Genetics Problems
The study of two traits at the same time
The ___________________________ states that if the genes that code
for traits are on different chromosomes, the alleles that code for the trait
will be inherited independently from one another
Dihybrid Genetics Problems
Dihybrid Genetics Problems
There are up to for 4 possible different male gametes (sperm) and up
to 4 possible different female gametes (eggs).
Mom's Possible Gametes
Dad's Genotype
Dad's Possible Gametes
AB
aB
AB
Ab
Ab
ab
AB
Ab
Finally, put 4 possible male gametes (sperm) across the top of the
___________ Punnett square and 4 possible female gametes (eggs)
across the side of the __________ Punnett square and combine the
gametes to find the all the possible genotypes and their ratios.
4 possible different male gametes
4 possible different female gametes
The tricky part is to come up with the with the gametes given the
genotypes of each parent.
Mom's Genotype
The Punnett square used for a __________________ involves using
a Punnett square that has spots for ____ possible different male
gametes (_______) and ____ possible different female gametes
(________).
4 possible different male gametes
4 possible different female gametes
Dihybrid Crosses
AB Ab AB Ab
AB
Ab
aB
ab
Dihybrid Crosses
F1 Generation
(Possible Genotypes)
Now we can cross 2 members of the F1 ( RrYy) generation to do a new
dihybrid genetics problem.
Phenotypic Ratio:
Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green
Dihybrid Crosses
F2 Generation
(Possible Genotypes)
Phenotypic Ratio:
Round Yellow: Round Green: Wrinkled Yellow: Wrinkled Green
Probability
§
what is the likelihood a specific trait will by
inherited in regards to both phenotype and genotype
§
the number of ways a specific event can occur (total
number of possible genetic outcomes)
Rules
1.
2.