1. GREGOR MENDEL
The monk who worked with?

2. MENDEL’S GOAL
EXPLAIN the PATTERN of HEREDITY from PARENT to OFFSPRING

3. WHY PEA PLANTS? EASY to GROW REPRODUCE offspring in a SHORT TIME
Get offspring results quickly
Only 7 traits (genes)
Each TRAIT HAS 2 FORMS (physical)
Avoid any confusion in results
MALE & FEMALE parts on flowers allow for
SELF-FERTILIZATION OR MENDEL could control breeding with CROSS FERTILIZING

4. HOW MENDEL CROSS FERTILIZED

5. FLOWERS & THEIR PARTS
Female flower parts
Male flower parts

6. MENDEL’S FIRST TRAIT EXPERIMENT- Flower Color
Two purebred parents are crossed
One parent has PP it has purple flowers
The other has pp white flowers
The offspring are all purple. Because they have one dominant gene P.
White recessive
offspring
Purple Dominant

7. Mendel’s Discovery HW assignment
Breeding Pea Color

8. MENDEL’S OBSERVATIONS OF OF 1ST PURE-BRED CROSS
The PARENT’s generation uses the code P.
They are PUREBRED plants. They had 2 genes that were both represented by the same letters, either PP for purple flowers or pp for white flower color.
The OFFSPRING generation uses the code F-1
offspring are Heterozygous, Pp. They have 2 genes, one dominant and one recessive.

9. MENDEL’S OBSERVATIONS OF 1ST PURE-BRED CROSS
ALL OFFSPRING had DOMINANT, purple flowers
None had the white flowers, or Recessive trait.

10. MENDEL’S 2ND EXPERIMENT SELF-FERTILIZATION CROSS
He bred the F-1GENERATION
Remember the F-1 were HYBRIDS, Pp
They had two genes, one dominant and one recessive.
Mendel did not realize this. He saw purple flowers. So he expected to see?
All purple offspring

11. F-2 RESULTS Some PURPLE & also some White flowered plants appear
HOW WAS THIS POSSIBLE?!
THE RECESSIVE TRAIT was always there in the genes of the flowers.
To get a white flower two recessive genes had to come together in an offspring to show up. pp
The phenotype ratio of offspring he had by flower color was 3:1 Three purple to one white.
The genotype ratio he got was 1 PP, 2Pp, 1 pp
it is written at 1:2:1

12. Mendel’s 2nd experiment
Crosses purebreds
Mendel’s 1st exp.
Mendel’s 2nd experiment
Crosses hybrids

13. Law of Dominance & Recessive Traits
Some traits are dominant over others
Some traits may not be expressed unless inherited on both genes

14. Principle of Segregation
For any trait, the pair of alleles from each parent separate and only one allele passes from each parent on to an offspring. Which allele is inherited is a due to chance.

15. PRINCIPLE OF INDEPENDENT ASSORTMENT
different pairs of alleles are passed to offspring independently of each other (during meiosis and fertilization)
Some offspring may not resemble their parents.

16. ABILITY TO PREDICT FUTURE EVENT
PROBABILITY
ABILITY TO PREDICT FUTURE EVENT
PREDICT THE FREQUENCY OF OFFSPRING TRAITS
EXAMPLE A COIN TOSS
WHAT are the CHANCES of GETTING HEADS with 1 COIN?
½, one side is heads, the other is tails
WHAT are the CHANCES of getting HEADS with 2 COINS?
½ x ½ =? ¼!

17. 2 trait cross-dihybrid Cross a homozygous X recessive
Gamete combos from each parent are only
RY or ry
F-1 generation
All are heterozygous genotypes

18. Cross of the F-1 offspring hybrids

19. DI-HYBRID CROSSES Use your Worksheet Di-hybrid Crosses If you need help, go to this tutorial