1. DO NOW: How could all of these puppies come from the same parents
DO NOW: How could all of these puppies come from the same parents? (Write down your answer)

3. Patterns of Inheritance: Genetics
Modern genetics began in 1860’s
Czech Monk- Gregor Mendel
Playing with peas in his garden
“THE MAN”

4. Gregor Mendel
Used peas to study how physical traits passed from parent to offspring - heredity
Mendel measured 7 traits in peas, each trait with 2 forms.
Examples of two Pea traits (Shape & Color)
that Mendel studied

5. How did Mendel do all this?
Step 1: Identify true breeding plants
When pure plants are self-fertilized, they ALWAYS produce offspring identical to the parent generation after generation.
How could you ensure self pollination?

6. Mendel crossed true breeding plants with two distinct traits using cross-fertilization.

7. Hybrids Offspring of two different true-breeding varieties.
P – parental generation
F1 – offspring of P generation
F2 – offspring of self fertilized or cross fertilized members of F1 generation

9. STOP PERIOD 3

10. Mendel’s 1st Rule The Law of Segregation:
For each trait (i.e. pod color or plant height) an individual has 2 factors
The 2 factors may be the same or different
When making kids, each parent will contribute only 1 factor
The 2 factors a parent has will separate when making a kid (Meiosis)

11. The Law of Segregation
Each parent will pass on 1 factor during sex (gamete production)
Kids get 1 factor (for each trait) from each parent...
Factors

12. The Factors
Each individual has 2 factors for each trait…pod color, height, eyes, hair...
If both factors for a trait are the same, you are homozygous for that trait…
If you have 2 different
factors for a trait, you are heterozygous for that trait
Period 3

13. How to Label these factors?
G for Green pods
Y for yellow pods
B for brown hair
x for blond hair
But…we don’t do this!!

14. The Factors
You have 2 factors, but only 1 factor for each trait is typically used (expressed)..
This is the dominant factor
The other one is the recessive factor

15. So; How we do Label the factors?
Dominant factor is written in
upper case… i.e. “B”
Recessive factor in lower case, using the dominant abbreviation.. i.e. “b”
B is for brown hair (which is dominant)
b is for blond

16. Mendel’s Factors = Genes
Every normal human has thousands of genes
Each gene describes the information for one human trait.
You have two genes for each trait
Where are these genes located?

18. How to Predict which factor you’ll give your kids?
Each parent has 2 factors for each trait
But, each gamete you produce has only 1 factor for each trait
Which factor goes to which kid?
Best described by a Punnett Square
Start Period 1, 7/8

19. Punnett Square..
Used to predict how offspring will get their share of factors…
Parents mate (x): BB X bb
What possible offspring will each make?
B B b
Male Gametes
Female
Gametes

20. Possible Offspring…. Or, F1 Generation
B B b Bb Bb Bb Bb b
Each F1 Offspring has the same traits for hair color… Bb

21. Try this one!
In summer squash, white fruit color is dominant to yellow fruit color.
What would the genotype and phenotype be for the F1 generation if the parental cross was homozygous white and yellow?

22. Another Example.. Trait for Seed Shape (S)
Text pg 181

23. Mendel’s 2nd Law Law of Independent Assortment:
Factors for each trait segregate into gametes independently of each other
The factor for hair color (B or b) will segregate independently of the factor for height (T or t)
Consider a dihybrid cross… Two traits at once
Example: Say Parents are Bbtt x bbTT

24. Dihybrid Cross If a Bbtt male mates with a bbTT female?
What are the possible gametes for each?

25. Male Bbtt x Female bbTT Bt bt bT bT BbTt bbTt bbTt BbTt gametes
New individuals
(with two factors
for each trait)
gametes
bbTt bT
BbTt

26. So What? What does Mendel and his Peas have to do with you?
Chromosomes and Heredity…

27. On Chromosomes We each have 46 chromosomes in each cell
23 chromosomes came from Mom, 23 from Dad
Each chromosome contains hundreds of genes…
An example using the FISH technique
of identifying the location of one gene
on a chromosome.

28. Gene location on Chromosomes