1. Genetics

2. Gregor Mendel
Gregor Mendel- an Austrian Monk who studied how pea plants pass on specific characteristics to their offspring
His experiments were later summarized in 2 Laws
Law of Segregation- only 1 allele passes from each parent to its offspring (the allele that is passed on is RANDOMLY selected)
Alleles- 2 forms of a gene
Law of Independent Assortment- Multiple offspring from the same parent can have different genes

3. Genetics Vocabulary
Genotype- the genes an individual has (ex. Aa, aa, AA)
Phenotype- the individual’s physical appearance (Tall, Short)
Homozygous- has 2 identical alleles for the same gene (AA, aa)
Heterozygous- has 2 different alleles for the same gene (Aa)

4. Incomplete Dominance
Incomplete Dominance- neither allele is dominant nor recessive, the heterozygous form blends
Ex: Homozygous Red Flower and Homozygous White Flower has all Pink Offspring

5. Co-Dominance
Co-Dominance- both versions of the trait are equal and BOTH are shown
Ex: Cows- Can be Red (RR), White(WW), or Roan (RW)

6. Sex-Linked Traits Traits that are carried on the X-Chromosome
Females: XX Males: XY
Tend to show up more often in males because Males only have 1 copy of the X Chromosome
Females can be carriers (have one copy of the gene, and one normal X Chromosome)

7. Pedigrees
A Pedigree is a diagram of family relationships that represent genetic relationships
Pedigrees are often used to determine the inheritance of sex- linked traits
Have disease/disorder/ trait: Fully Shaded
Carrier: half shaded
No disease/disorder/trait: not shaded

8. Genetic Disorders- Autosomal Recessive
Autosomal Recessive- need both recessive alleles to have the disease
Tay-Sachs Disease
Fat accumulates in brain destroying tissue
Severe impairment and death
Cystic Fibrosis
Most common in Caucasian population
Mucus in respiratory tract, difficulty breathing
Phenylketonuria (PKU)
Lack enzyme for normal metasbolism

9. Genetic Disorders- Autosomal Dominant
Autosomal Dominant- Need one copy of the dominant allele to have the disease

10. Multiple Alleles More than 2 alleles code for a single trait
Ex: There are 3 alleles that code for an individual’s Blood Type (A,B,O)
A and B show co-dominance (a heterozygous individual shows BOTH alleles, AB)
A and B are both Dominant to the O allele
An individual can have the genotype AA, AO, AB, BB, BO, or OO and the phenotype Type A blood, Type B blood, Type AB blood, or Type O blood

11. Polygenic Inheritance
Multiple GENES code for one trait
Ex: Height, Skin Color