Fr. Gregor Mendel

Father of Genetics1822 - 1884

Pre-Mendelian Ideas on Inheritance

• Blending

• Homunculus

Homunculus

Why was Mendel Successful?

1. Good Research Organism (pea plant)

* Small, easy to grow in large numbers

* short life cycle could test several generations

* Could cross or self-pollinate

Could cross or self-pollinate(Why was this important????)

Why was Mendel Successful?

1. Good Research Organism (pea plant)

* Small, easy to grow in large numbers

* short life cycle could test several generations

* Could cross or self-pollinate

* Were “politically correct” (Explain!)

Why was Mendel Successful?

1. Good Research Organism (pea plant)

2. Had good math/statistical background

3. Picked good pairs of traits to study:ex: Tall/shortex: (find for HW!)

Mendel’s Experiments

Experiment #1

• Created “pure breeding” tall plants

• Created “pure breeding” short plants

Experiment #1 (cont)Crossed “pure” tall x “pure” short

Experiment #1 (cont)

Crossed two F1 plants (Monohybrid Cross!)

Now we know….

Now we know….

Mendel’s Laws

• Law/Principle of Dominance

• Law/Principle of Segregation

• Principle of Independent Assortment

figure 13-04_02