Mendel’s Legacy (11-1)

Gregor Mendel A. Monk -1842 B. Tended the gardens. C. Best known for work with garden pea plants.

Mendel’s Garden Peas A. Pea plants had 7 distinct traits, or characteristics B. Seven traits: 1. Height: Tall and short 2. Flower position: axial or terminal 3. Pod color: green or yellow 4. Pod appearance: inflated or constricted 5. Seed texture: smooth or wrinkly 6. Flower color: purple or white 7. Seed color: yellow or green

Mendel’s Methods A. Pollination: when pollen grains from the male flower is transferred to the female flower. 1. male – anthers 2. female – stigma B. Self-pollination: when pollen is transferred from the anthers to stigma of the same flower, or of the same plant.

A. Mendel studied each characteristic alone by producing pure plants. C. Cross-pollination: pollen from one plant is transferred to the stigma of a different plant. D. Mendel controlled the pollination of flowers by removing the anthers of plants and doing the pollinating himself. This controlled the traits that would be passed on. 4. Mendel’s Experiment A. Mendel studied each characteristic alone by producing pure plants. B. Pure: plants will always produce offspring with that trait. C. Strain: term for plants pure for that trait .

Pure plants

E. He then crossed two different pure plants to get the offspring D. P1 generation: the parent generation for each of his 14 strains E. He then crossed two different pure plants to get the offspring F. F1 generation: first filial generation G. F2 generation: second filial generation H. He then counted the number of offspring with each trait and found the ratios of them Figure 11:4, p. 265, Fig. 11;5, p. 266

Mendel’s Results and Conclusions A. By looking at his results, he found that each trait was controlled by two separate factors. B. Dominant factor: one that masks, or dominates the other factor. C. Recessive factor: one that is hidden by the dominant factor and is only seen if paired with another recessive factor.

D. Law of Segregation: a pair of factors is segregated or separated during the formation of gametes.

Chromosomes and Genes A. Molecular genetics: study of the structure and function of chromosomes and genes. B. Chromosomes occur in pairs, and so do genes. C. Alleles: the alternative forms of a gene represented by letters. D. Dominant traits are represented by capital letters and recessive traits are represented by lower case letters.