1. Genetics
Gregor Mendel
*The father of genetics

2. Mendel was the first to carry out studies of heredity.
Heredity --> passing on of characteristics from parent to offspring

3. Genetics - branch of biology that studies heredity.
Characteristics that are inherited are called traits.
Mendel predicted how traits are transferred from one generation to the next --> using pea plants.

4. He crossed plants with different traits.
Example: A tall plant X short plant
Green seeded plant X Yellow seeded

5. Genes are the basic unit of inheritance.
-> located on our chromosomes.
One gene is inherited from the female parent and one from the male.
How genes work…

7. If one trait is masked or covered up by the other, the trait that hides the other is dominant.
(capital letters: A, B, R, Y)
The trait that is covered up or hidden is recessive.
(lower case letters: a, b, r, y)

8. Genes work in pairs!
If both traits are dominant (CAPITAL), the organism is homozygous dominant.
If both traits are recessive (lower case), the organism is homozygous recessive.
These organisms are purebred.
Homozygous means “SAME”

9. Heterozygous individuals are also called carriers.
If one trait is dominant and one is recessive, the organism is heterozygous. (capital & lower case)
These organisms are hybrids.
Heterozygous means “different”!
Heterozygous individuals are also called carriers.
--> They “carry” the recessive gene.

10. Alleles * Allele refers to the “letters.”
Genes exist in alternative forms.
--> These different gene forms are called alleles.
* Allele refers to the “letters.”

11. Punnett Squares
* Used to determine the probability (or ratio) of expected offspring
Genotype: organism’s gene combination
Phenotype: organism’s physical appearance, the way it looks