1. Probability and Genetics

2. Genes and Alleles Gene - segment of DNA that codes for a traits
Alleles - different versions of a gene
Gene
Alleles
Eye color
Brown, Blue
Flower color
Purple, White

3. Genotypes and Phenotypes
Genotype - genetic makeup (which alleles do they have?)
Phenotype - physical trait (due to the genotype)

4. Heterozygous and Homozygous
Heterozygous - 2 different alleles for a gene
Homozygous - 2 of the same alleles for a gene

5. Law of Dominance
Dominant allele - one or two copies of this allele results in the dominant trait
Recessive allele - you need two copies of this allele to show the recessive trait (or you need to NOT have the dominant allele)

7. Probability and Genetics
Review

8. What role does probability play in genetics?
Probability is the likelihood that something will happen
Which allele you pass on is random - like flipping a coin!

9. What about sample size? More trials gets closer to expected results…
Flip a coin twice…would you be surprised if you got 2 heads?
Flip a coin 100 times…would you be surprised if you got 80 heads, 20 tails?

10. Are predictions reality?
It’s just odds…

11. What does meiosis have to do with inheritance?
Meiosis splits up alleles
Each gamete has a different combination of alleles

12. How is variation guaranteed in offspring?
Crossing over

13. How is variation guaranteed in offspring?
Independent assortment

14. How is variation guaranteed in offspring?
Random Fertilization
Men make 200,000 sperm a day
Which one reaches the egg??
Women start off at birth with 200,000 eggs
Which one will be released that month??

15. How do we use Punnett Squares?
We use Punnett Squares to PREDICT the outcomes of matings (or crosses)
It’s not necessarily going to turn out that way
These are just odds or probabilities