1. Mendel’s Principles of Inheritance
By INSERT YOUR NAME HERE

2. Principle of Dominance Mendel’s Observations
Mendel observed that all plants in the next generation, called the F1 generation, showed the presence of yellow seeds.
None of the offspring had green seeds.
The green allele seems to completely disappear in this generation.
w w Rw R
Key
R = round
w = wrinkled

3. Principle of Dominance My Conclusions
My dad has blue eyes and my mom has brown eyes. But, all 3 of us kids have brown eyes.
This makes me guess that brown is a dominant gene for
eye color in humans.
l l Rl R
Key
R = brown
l = blue

4. Principle of Segregation Mendel’s Observations
Mendel observed that approximately 3/4th of the F2 generation plants showed the presence of yellow seeds.
The remaining 1/4th show green seeds.
The observations were consistent, with any character that Mendel studied.
R w RR Rw ww R w

5. Principle of Segregation My Conclusions
Thinking about my example with eye color in my family.
If I marry someone with brown eyes, but the same mix of brown and
blue eye color alleles from their parents, then some of our kids might
have blue eyes, based on the probability of the recessive blue trait
showing up as both alleles for one of our kids.
R l RR Rl ll R l
Key
R = brown
l = blue

6. Principle of Independent Assortment Mendel’s Observations
When a true breeding plant for yellow round seeds is crossed with a true breeding plant for green wrinkled seeds, the F1 offspring were all yellow round.
Then when F2 plants were obtained after F1 self-fertilization, 9/16th of the plants showed the dominant parental trait and 1/16th showed the recessive parental trait.
However, the remaining plants, about 6:16, express phenotypes different from those of either of the parents.
In our example, these would be yellow wrinkled and green round seeds.

7. Principle of Independent Assortment Punnett Square
Cross a tall plant with lavender flowers with a short plant with white flowers. Then take an F2 generation cross
TL Tw sL sw
TTLL
TTLw
TsLL
TsLw
TTww
Tsww
ssLL
ssLw
ssww TL Tw sL sw
Key
T = tall
s = short
L = lavendar
w = white

8. Principle of Independent Assortment My Conclusions
Thinking one more time about my example with eye color in my family.
If I marry someone with blue eyes this time and if they have blond hair and
I have black hair, we will not just produce children with either black hair
brown eyes combinations or blond hair blue eyes combinations. Our kids
may well have blond hair and brown eyes or black hair and blue eyes –
new, unique combinations that are not like either myself or my spouse. In fact, if we both have a recessive red hair allele, we may end up with some kids with blue eyes and red hair or some other unique combination.