1. IN 147 Headings Vocabulary Important Info
Genetic Variation
IN 147
Headings
Vocabulary
Important Info

2. The Law of Segregation Mendel’s 1st Law
The 2 alleles of each gene pair separate into different gametes (egg or sperm) during meiosis.

3. The Law of Independent Assortment
Mendel’s 2nd Law
Independent Assortment:
Genes that are inherited separately… Do NOT influence the inheritance of others
Alleles segregate independently during meiosis
Some ALLELES go to one gamete and some to another

4. INCOMPLETE DOMINANCE Incompletely dominance:
Genes are neither dominant nor recessive= they mix!!!
Genotype is heterozygous (hybrid--Hh)
Phenotype is between two parents
Dominant gene cannot fully mask the recessive
Ex: white flower x red flower = pink flowers

5. CODOMINANCE Codominance: Offspring shows phenotype of neither parent
Both alleles are DOMINANT!!!
Ex: black chicken x white chicken = checkered chicken

6. MULTIPLE ALLELES Multiple alleles: Two OR More alleles control a trait
You still will only have two of these alleles. 
Ex: height, hair color, eye color and blood type  
There are 3 different alleles for blood: 
(Type A) = IA IA or IA i
(Type B) = IB IB or IB i
(Type AB) = IA IB
(Type O) = ii

7. Sex-Linked Alleles Sex-linked alleles:
controlled by genes located on sex chromosomes (XX or XY)
Usually carried on X chromosome
Since females are XX, they are usually carriers of the trait
Since males are XY, they have a higher tendency for inheritance of trait

8. If trait is X-linked, MALES:
pass it to all daughters
none to sons
If trait is X-linked, MOTHERS:
have 50/50 chance of passing it to all of their children
Ex: colorblindness, hemophilia, male pattern baldness