1. Mendelian Genetics

2. Gregor Johann Mendel 1822-1884 Austrian “Father of Modern Genetics”
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3. Inheritance
What is the difference between a characteristic and a trait?
Give examples of each.
Up until Mendel, the prevailing theory of inheritance was that the traits of offspring are “blends” of the parents
A plant with red flowers crossed with a plant with white flowers would give offspring with pink flowers

4. Mendel’s Experiments
Between 1856 and 1863, working as a schoolteacher in a monastery, Mendel grew and tested over 29,000 pea plants looking at the inheritance of traits
Picked characteristics that had 2 distinct traits
Performed simple crosses in which the plants differed in only one trait
Monohybrid cross

5. Pea Flower Color

6. True-breeding
What was Mendel’s definition of true-breeding? What do we now call true-breeding?

7. Generations P generation: parental
F1 generation: first filial generation
Filial: related to your offspring
F2 generation: second filial generation
How is the F1 related to the F2 generation?
How is the P generation relation to the F2 generation?

8. Mendel’s results
Performed many different monohybrid crosses and always found the 3:1 ratio of traits in the F2 generation
Flower color
Seed shape
Seed color
Pod shape
Pod color
Flower position
Stem length (height)

9. Mendel’s Conclusions
The trait he saw expressed in the F1 generation he described as dominant
The trait that is masked in the F1 and reappears in the F2 is the recessive

10. Mendel’s Conclusions Law of Segregation
Be able to explain the two parts of the law of segregation.

11. Allele: Genes and Alleles
Since there are two copies of each chromosome in somatic cells, it means there are two copies of each gene
Allele: