1. Mendelian Genetics

2. Mendel laid the groundwork for genetics.
Genetics is the study of inheritance patterns and variation.
Gregor Mendel showed that traits are inherited as units.

3. is the passing of traits from one generation to the next.
Heredity
is the passing of traits from one generation to the next.
A trait is a distinguishing characteristic or quality.

4. DNA Review…..
DNA, deoxyribonucleic acid, is the set of chemicals that tells all of the cells in our body what to do. It is like a set of directions, and is what makes each individual unique.
A chromosome is made up of DNA. It is the long chain of DNA that has been coiled up tightly. These chromosomes, or pieces of DNA, contain genes.
Homologous chromosomes are chromosomes that have the same genes, in the same location. You get one of each chromosome in a homologous pair from each parent.
EX: Chromosome #1 you have one from mom and one from dad, and they are homologous because they contain the same genes.

5. DNA
Genes
Alleles
Genes are segments of DNA on a chromosome that has directions for specific traits.
EX: Hair color
An allele is an alternate (different) form of a gene.
EX: allele for brown hair (H), allele for blonde hair (h)

6. Alleles Recessive allele Dominant allele
An allele whose trait always shows up in the organism when the allele is present.
The dominant allele is represented by a capital letter (Brown hair is dominant = H)
Recessive allele
An allele whose trait is hidden when paired with a dominant allele. The only way a recessive allele shows up is if the organism does not have a dominant allele.
This is represented by a lowercase letter (blonde hair is recessive = h)
Ended here with A

7. We use the same letter to represent BOTH alleles!!

8. There are two alleles for each gene…
Homozygous
Heterozygous
This is the term used when an organism has two identical alleles for a trait.
Ex: HH or hh
This is the term used when an organism has two different alleles for a trait.
Ex: Hh
Stopped here with class D

9. Genotype vs. Phenotype
Genotype: actual alleles from parents (letters; HH)
Phenotype: physical appearance of organism (No letters. What does it look like? What traits does it have? Brown hair or blonde hair?)

10. Let’s Try! Let’s use freckles. Having freckles is dominant = F
No freckles is recessive = f
How would you show an individuals genotype if they were:
Homozygous dominant for freckles?
Homozygous recessive for freckles?
Heterozygous for freckles?

11. Write the genotype for an individual that is:
Brown eyes = B
Blue eyes = b
Write the genotype for an individual that is:
Blue eyed:________________________
Homozygous dominant for eye color:____________
Heterozygous for eye color:___________________
Homozygous recessive for eye color:________
What genotypes can a person have if they have brown eyes?_____________
Ended here with C

12. A purebred is an organism that always produces offspring with the same form of a trait as the parent. This is also referred to as homozygous. A hybrid is an organism that has two different alleles for a trait. This is also referred to as heterozygous.

13. Only 1 allele from each parent is in each box.
Each box ends up with 2 total alleles, one from the mother and one from the father.

14. __________X__________
Monohybrid Cross
Cross involving one contrasting trait
Use a Punnett square to predict probabilities…
(let’s use F)
Cross a heterozygous purple flower with a homozygous recessive white flower.
__________X__________