Aim: Why did Gregor Mendel’s experiments with pea plants lead to the science of genetics? Text Ch 11 Introduction to Genetics Read pages 262 – 269 HW # 6 pg. 266 q 1-5 on loose leaf pg. 269 q 1-5

Gregor Mendel, The Father of Genetics The science of genetics was born in 1856, when an Austrian monk named Gregor Mendel performed an historic series of experiments on pea plants, thus discovering the laws of heredity.

Seed Shape Flower Position Seed Coat Color Seed Color Pod Color Plant Height Pod Shape Round Wrinkled Round Yellow Green Gray White Smooth Constricted Green Yellow Axial Terminal Tall Short YellowGraySmoothGreenAxialTall Section 11-1 Figure 11-3 Mendel’s Seven F 1 Crosses on Pea Plants Go to Section: Characteristics of the Pea Plant

Section 11-2 Tt X Tt Cross Go to Section: Punnett Square to determine the probability of offspring P Tall X Short TT tt F 1 Key P = parents F 1 = First generation F 2 = Second generation

Section 11-2 Tt X Tt Cross Go to Section: F 1 Hybrid Tall X Hybrid Tall F 2 generation

Groups: Work out these probabilities using the Punnett Square PRound X Wrinkled seed shape F 1 F 2 PYellow X Green seed color F 1 F 2 PGray X White seed coat color F 1 F 2

Use a 16 box Punnett Square to follow 2 traits of the pea plant F 1 dihybrid tall yellow X dihybrid tall yellow

Incomplete Dominance Both alleles have an effect on the phenotype of the organism

concluded that which is called the Gregor Mendel Law of Dominance Law of Segregation Pea plants “Factors” determine traits Some alleles are dominant, and some alleles are recessive Alleles are separated during gamete formation Section 11-3 Concept Map Go to Section: experimented with Mendel’s Principles Today we know “Factors” are genes