Chapter 11: Introduction to Genetics
CH 11.1 (Pg. 308-312): The Work of Gregor Mendel
What is Genetics? Genetics: the study of heredity Heredity: the passing of characteristics from parents to offspring Gregor Mendel is known as the ‘Father of Genetics’ In 1800s he discovered how traits are inherited
Mendel’s Experiments Studied ordinary garden peas Small and easy to grow Have many different traits, or specific characteristics (ex: color, height, shape, etc) Used peas as a ‘model system’ to understand other organisms
Fertilization Is the process of male and female reproductive cells joining Occurs in pea plants when pollen (male cells) join with eggs (female cells) Pea plants can be self-fertilized or cross-fertilized Male Parts Female Parts
Self-Fertilization Is when sperm cells fertilize egg cells from the same flower Offspring inherits all of its traits from one parent Produces identical offspring Mendel used these plants in his experiments
Cross-Fertilization When one plant reproduces with a different plant Offspring have two different parents Not identical to their parents Mendel studied 7 pea plant traits Crossed plants with contrasting characteristics Produced hybrids: offspring of parents with different traits
Mendel’s Seven Plant Crosses Parental Generation (P): the original pair of plants First Filial Generation (F1): the offspring of the original pair
Mendel’s Conclusions Gene that determines hair type An individual’s characteristics are determined by factors that are passed from one parental generation to the next Genes: factors passed from parent to offspring Alleles: different forms of one gene Gene that determines hair type Curly Hair Straight Hair
Mendel’s Conclusions Gene that determines hair type 2) Principle of Dominance: some alleles are dominant and others are recessive If dominant allele present the individual will have that form of the trait If dominant allele absent they will have the recessive form of the trait Gene that determines hair type Curly Hair Straight Hair Dominant (C) Recessive (c)