1. Introduction to Genetics

2. Heredity Also know as Biological inheritance. Also know as Biological inheritance. It is the key to differences between species. It is the key to differences between species. The branch of biology that studies heredity is called Genetics. The branch of biology that studies heredity is called Genetics.

3. History of Heredity Gregor Mendel- Monk who worked with pea plants to better understand heredity, sometimes referred to as the father of modern genetics, came up with Principle of Dominance. Gregor Mendel- Monk who worked with pea plants to better understand heredity, sometimes referred to as the father of modern genetics, came up with Principle of Dominance. The principle of dominance states that some alleles are dominant and some are recessive. The principle of dominance states that some alleles are dominant and some are recessive. The dominant allele is seen when in combination with itself or a recessive allele. The dominant allele is seen when in combination with itself or a recessive allele. The recessive allele is never seen when in combination with the dominant, it is only seen with in combination with itself. The recessive allele is never seen when in combination with the dominant, it is only seen with in combination with itself. This doesn’t apply to all genes. This doesn’t apply to all genes.

4. Definitions of Mendel’s Work Purebred- Produces offspring identical to the parent. Purebred- Produces offspring identical to the parent. Trait- Easily observable characteristic (shape, color, size, etc.) Trait- Easily observable characteristic (shape, color, size, etc.) Hybrids- Organism produces by crossing parents with differing characteristics. Hybrids- Organism produces by crossing parents with differing characteristics. Gene- Factor that controls traits. Gene- Factor that controls traits. Alleles- The different forms of a gene. Alleles- The different forms of a gene.

5. Definitions of Segregation Phenotype- Physical characteristic of an organism, the visible expression of an allele. Phenotype- Physical characteristic of an organism, the visible expression of an allele. Genotype- Genetic makeup of an organism, the actually allele combination. Genotype- Genetic makeup of an organism, the actually allele combination. Homozygous- An organism that has two identical alleles for a particular trait. Homozygous- An organism that has two identical alleles for a particular trait. Heterozygous- An organism that has two different alleles for a particular trait. Heterozygous- An organism that has two different alleles for a particular trait.

6. Segregation We use a Punnett Square to visualize and predict the outcome of crossings. Punnett squares are used to predict the probability of a cross without actually crossing organisms. We use a Punnett Square to visualize and predict the outcome of crossings. Punnett squares are used to predict the probability of a cross without actually crossing organisms. –Single Factor –Double Factor Segregation- The separation of alleles during gamete formation. Segregation- The separation of alleles during gamete formation.

7. The Two-Factor Crosses on Punnett Squares If two genes are connected in some way then the dominant alleles and recessive alleles will be segregated as matched sets into gametes. If two genes are connected in some way then the dominant alleles and recessive alleles will be segregated as matched sets into gametes. If genes are not connected then they should segregate independently or undergo Independent Assortment. If genes are not connected then they should segregate independently or undergo Independent Assortment. Probability- The likelihood that a particular event can occur. Probability- The likelihood that a particular event can occur.