Introduction to Mendelian Genetics

Mendelian genetics refers to the principles of inheritance as described by Gregor Mendel, an Austrian scientist who conducted groundbreaking experiments with pea plants in the mid-19th century. Mendelian genetics laid the foundation for our understanding of how traits are passed from one generation to the next.

Slides align to Chapter 12, Section 1, Miller and Levine Biology (Bee Book)

Key concepts of Mendelian genetics include:

  1. Genes and Alleles: Mendel proposed the existence of discrete units of heredity, which we now call genes. Each gene can have different forms called alleles.

  2. Dominance and Recessiveness: Mendel observed that some alleles are dominant, meaning that they mask the effects of recessive alleles when present. Recessive alleles are only expressed when an individual inherits two copies of the recessive allele.

  3. Segregation: During the formation of gametes (sperm and egg cells), alleles segregate or separate from each other. Each gamete carries only one allele for each gene.

  4. Independent Assortment: Mendel discovered that genes located on different chromosomes segregate independently during the formation of gametes. This principle is known as independent assortment.

  5. Punnett Squares: Punnett squares are tools used to predict the possible genetic outcomes of a cross between two individuals. They help illustrate the probability of different combinations of alleles in offspring.

  6. Genotype and Phenotype: The genetic makeup of an individual is called the genotype, while the observable traits or characteristics are referred to as the phenotype.

pea plantPractice Sets on Mendelian Genetics

Simple Genetics Practice – using mendelian genetics and Punnett squares

Peas, Please – practice setting up squares for basic Mendelian traits in pea plants

Bunny Genetic Crosses with two traits – basic crosses, uses Punnett squares

Practice Punnett Squares with Skinny Pigs – hairless guinea pigs are the result of a recessive gene (Key, TpT)

Horse Genetics – basic practice worksheet on monohybrid and dihybrid crosses, using a gait trait found in horses

Fruit Fly Genetics (Vg) – practice worksheet on vestigial wing flies (recessive trait)