1. Genetics
The study of heredity
polydactyly

2. Heredity
The passing on of traits (characteristics) from parents to offspring
China McClain & sisters (Ant Farm)

3. Examples of Traits Hair color Eye color Height Intelligence
Ability to roll your tongue
Mid-digital hair
Attachment of ear lobe
Ability to taste bitter

4. Traits are controlled by genes
…. so then what are genes?
Gene
Controls how an organism develops
It is a specific segment of DNA located on a chromosome
Each trait has two alleles
…. so then what are alleles?
Allele
Different forms of the same gene
How are genes passed on? By your parents in reprododo

5. Alleles Dominant allele Recessive allele
Produces a trait that is observed in the offspring whenever present
Represented with an uppercase letter
Recessive allele
produces a trait that is observed in the offspring only if both alleles are recessive.
Otherwise, the trait disappears
Represented with a lowercase letter

6. --The separation of alleles during meiosis to form gametes
--The separation of alleles during meiosis to form gametes. ( Sex cells: egg/sperm)
The law of independent assortment states that genes for different traits can segregate or switch independently during the formation of gamates.

7. For example:
Eye Color
Dominant Color: Brown = B
Recessive Color : Blue = b
One allele from each parent because two alleles form a trait, therefore…
B B b b B b
Brown
Blue
Brown

8. Phenotype BB bb Bb The way an organism looks (physical)
For example:
BB bb Bb
Phenotype: Brown
Blue
Brown

9. Genotype Homozygous (same) Heterozygous (one of each) BB bb Bb
The gene combination of an organism (genes)
Homozygous (same)
If the two alleles of a trait are the same (BB or bb)
Heterozygous (one of each)
If the two alleles for a trait are different (Bb)
For example:
BB bb Bb
Genotype: Homozygous
Dominant
Homozygous
recessive
Heterozygous

10. How did we figure this stuff out?!
Gregor Mendel was a monk from Austria born in 1822
He made observations of his father’s orchard and decided he could predict the kinds of flowers a plant could produce…if he knew something about the parent plants.
After 8 years of carefully carrying out the scientific method, Mendel wrote a paper about inheritance in pea plants.

11. Traits of Pea Plants

12. Punnett Square
Diagram used to predict genetic crosses.

13. b b b Individuals with identical alleles are called homozygous.
Individuals with different alleles are called heterozygous.
Phenotype-physical characteristics
Genotype-genetic makeup
How to use a Punnett Square
-choose a letter to represent the alleles
in the cross
-write the genotypes of the parents
-determine the possible gametes
(reproductive cells)that the parents can
Produce.
-enter the possible gametes at the
top and side of the Punnett Square
b b b