Essential Question •How are patterns of inheritance studied? By the end of this lesson, you should be able to explain how patterns of heredity can be predicted by Punnett squares.
•Define the following:
•Ratio – an expression that compares two quantities
•Probability – the likelihood of a specific outcome
•Punnett Square – a graphic used to predict the possible genotypes of offspring in a given cross
In guinea pigs, the dominant B allele is responsible for black fur, while the recessive b allele is responsible for brown fur. Record the Punnett square in your notebook. Use the Punnett square to find the probability of this cross resulting in offspring with brown fur.
Create your own Punnett Square! Decide what your guinea pig parents alleles are and then trade with your shoulder partner to find the probability of the offspring's phenotype.
• Skinny pigs are guinea pigs with little to no hair.
• Read the following statements with your table / shoulder partner to figure out the parent’s genotypes
•Use H for hair and h for no hair
Skinny Pig X Skinny Pig
When you breed two Skinny Pigs together, 100% of their babies will all be Skinny Pigs and hairless. What are the parent genotypes? Both parents would be: hh, hh
Skinny Pig X Skinny Pig Gene Carrier
There is a 50-75% or about half chance that the babies bred by a Skinny Pig and a haired Skinny pig gene carrier, will have hairless Skinny pig babies. The rest of the babies will just be skinny pig gene carriers.
There is only a 25% chance that 1 or so hairless skinny babies will be born in these litters. What are the parent genotypes? Skinny pig – hh Skinny pig gene carrier - Hh
Skinny Pig X Regular haired breed guinea pig (not a gene carrier of skinny)
None of them will be a hairless skinny pig. There is a chance that most of the babies will be haired Skinny Pig gene carriers which can then be bred back to the Skinny Pig.
What are the parent genotypes?
Skinny pig – hh Regular haired breed guinea pig (not a gene carrier of skinny) - HH