1. Genetics

2. Study of heredity and the variation of inherited characteristics
Heredity- the biological process where parents pass on certain genes to their offspring
Genetics

3. History Gregor Mendel Known as the “father of modern genetics”
As an Austrian monk and botanist, he was able to come up with the basic principles about heredity
Majority of his research was done on pea plants
History

4. 1. All organisms produce more offspring than can survive.
2. Some organisms in a species survive and reproduce better than others.
3. Organisms in a species show wide variation.
4. Variations are inherited and passed on to the next generation.
Without Mendel, Charles Darwin’s idea of Natural Selection could not be explained

5. The Principles of Genetics
Variation is random and created by:
Mutations
Crossing over in meiosis
Independent Assortment*
Random mating
The Principles of Genetics

6. Traits are genetically determined characteristics; a gene
Alleles will make up the alternative forms of that gene.
Ex. Hair Color- trait/gene
Blonde, Black, Brown, Red- alleles
What Makes a Trait?

7. List 5 different traits or genes and 3 Alleles for each
_______________:_______________
Trait/genes: Alleles

8. Characteristics of Traits
Genotype
Phenotype
The genetic make up
Usually represented by a letter or letters
Ex. A or Aa
The observable trait/gene
The physical characteristic
Ex. Brown hair, Green eyes
Characteristics of Traits

9. Characteristics of Traits
Dominant
Recessive
The trait or allele that will mask(or dominate) over the other.
Shows up more often
Represented by a capital letter
Ex. A
The trait or allele that is being masked(or covered).
Shows up less often
Represented by a lower case letter
Ex. a
Characteristics of Traits

10. Characteristics of Traits
Homozygous
Heterozygous
Both genotype alleles are the same
Ex. AA or aa, BB or bb
Both genotype alleles are different
Ex. Aa or Bb
Characteristics of Traits

11. practice What would be an example of …….
Homozygous Dominant (use the letter “H”)?
_ HH___
Heterozygous Dominant?
___Hh__ ___
Homozygous Recessive?
__hh______
practice

12. Practice Round eyes are dominant to oval eyes. List the genotypes
__RR_____
__Rr_____
-Oval
__rr_______
Practice

13. Practice Small ears are dominant to big ears. List the phenotypes. -AA

14. Mendel’s 3 Laws

15. Mendel’s 1st Law 1st Law – Law of Dominance
One allele from the pair will be expressed while the other is unexpressed.
The allele that is expressed is considered dominant. The unexpressed allele is recessive.
Example: Black hair is dominant to Blonde hair
Mendel’s 1st Law 15

16. Mendel 2nd Law 2nd Law – Law of Segregation
States that during meiosis two alleles will separate from each trait.
Recall Meiosis – you create gametes. Law of Segregation ensures that each gamete will have one allele from the allele pair.
Mendel 2nd Law 16

17. Mendel’s 3rd Law 3rd Law-Law of Independent Assortment
States that alleles distribute randomly or independently during meiosis.
F-O-I-L
YyRr – gametes ____YR______Gamete 1
_______Yr______Gamete 2
_______yR______Gamete 3
_______yr______Gamete 4
Mendel’s 3rd Law 17

18. F-O-I-L A a B b “INSIDE-OUTSIDE” F- First O- Outer I-Inner L-Last AaBb
F-AB
O-Ab
I-aB
L-ab
AaBb
A a B b
“INSIDE-OUTSIDE”
F-O-I-L

19. PRACTICE AABb aaBb Aabb
How many different allele combinations were created?
PRACTICE

20. A punnett square is a visual aid that is used to view traits.
Gives you a probability for possible outcomes when traits are crossed
Punnett Squares

21. Monohybrid Punnett Squares
Monohybrids are used to view the outcomes in offspring examining only one trait
Monohybrid Punnett Squares 21

22. Genotype and Phenotype Ratio
Genotype Ratio:
#Homozygous Dominant(BB) : #Heterozygous(Bb) : #Homozygous Recessive(bb)
Ex. 0:2:2
Phenotype Ratio:
#Dominant Trait : #Recessive Trait
Ex. 2:2
Genotype and Phenotype Ratio

23. Dihybrids Peas Looks at the possibilities of two different traits.
Two Traits:
Shape (Round or Wrinkled)
Color (Yellow or Green)
-RrYy x RrYy
FOIL-
R r Y y
Dihybrids
Looks at the possibilities of
two different traits. 23

24. RrYy x RrYy