January 27, 2015 Materials: Pen/pencil Notebook Packet Cells Heredity bookAgenda AGENDA AGENDA Daily question Daily question Gregor Mendel notes Gregor Mendel notes Reading activity Reading activity Brain pop Brain pop DQ: What traits did you obtain from your parents, list 2?

Chapter 4 Vocabulary

GREGOR MENDEL “The Father of Genetics”

Austrian monk from the 1800’s. Studied over 30,000 specimens of pea plants during an 8 year period. He studied 7 characteristics of pea plants: 1. Plant height (dwarf vs. tall) 2. Flower & pod position (on side or top of stem) 3. Seed shape (round or wrinkled) 4. Seed color (green or yellow) 5. Pod shape (inflated or constricted) 6. Pod color (green or yellow) 7. Flower color (white or purple)

True-breeder: Will always produce offspring w/ a particular trait when allowed to breed naturally. “Pure bred.” Non-true-breeder: Will produce offspring that are not necessarily identical to itself.

Mendel’s 1 st experiment crossed a true-breeding plant of regular height w/ a true-breeding plant of short height. All of the plants were of regular height. → 1 st Generation. The short trait seemed to have disappeared.

Next, Mendel let the 1 st generation self-pollinate w/ each other → 2 nd Generation. 75% of the plants were regular height, 25% were short. He repeated this experiment for multiple traits – flower color, pod color, etc. He found that similar results were obtained in each experiment.

He realized that… 1.Organisms must have 2 “factors” for each possible trait, one from each parent. 2.Some traits can be masked by others. Heredity Video

HEREDITY AND GENETICS NOTES

 Inherited Traits  Examples: Dimples, Freckles, Eye Color, Hair Color, Height, Body Type PARENTS AND OFFSPRING ARE SIMILAR

 Individuals inherit genes from PARENTS  Genes are located on CHROMOSOMES  Each parent contributes ONE gene for each trait  Genes code for TRAITS  Humans have 46 chromosomes, 23 from each parent  Different forms of the same gene are ALLELES  EX: Alleles for the eye color gene: blue, green, brown, hazel, etc. GENES ARE ON CHROMOSOME PAIRS

 He studied…  How traits were inherited in pea plants!  Mendel’s Conclusions  Traits inherited in patterns  Some traits were stronger than others GREGOR MENDEL’S DISCOVERIES ABOUT HEREDITY

 An allele is a different form of a gene  Phenotype  Physical or observable traits  Ex: blue eyes, black hair, etc  Phenotype is determined by GENOTYPE  Genotype  Gene pairs, or gene combo  Represented by 2 letters (one for each allele)  EX: Bb, TT, rr  2 alleles make a GENOTYPE  Dominant  Stronger trait, hides recessive trait  Represented by A CAPITAL LETTER  EX: B, T, R  Recessive  Weaker trait, sometimes hidden  Represented by a lower case letter  EX: b, t, r ALLELES INTERACT TO PRODUCE TRAITS