Genetics and Heredity

1. Genetics and Heredity

2. What is heredity? • The passing on of characteristics from parents to offspring. • Genetics is the branch of biology that studies heredity • the characteristics that are inherited are traits.

3. Father of Modern Genetics • Gregor Mendel – Augustinian Monk in 1856 to 1863 • Experimented on heredity and traits • First person to be able to predict traits

4. Mendel’s Subject • He chose pea plants, which reproduce sexually, which means they have two distinct sex cells, male and female. • sex cells are called gametes. • the transfer of male pollen grainsto the pistil of a flower is calledpollination • the uniting of male and female gametes is called fertilization

5. Crosses • A hybrid is the offspring of parents that have different forms of a trait, such as tall and short. • Mendel first did monohybrid crosses, which means he was looking at only one trait.

6. Mendel’s crosses

7. The rule of dominance • Every trait iscoded for bytwo genes • the genes have different forms called Alleles. • Alleles are either dominant, recessive or co-dominant

8. the law of segregation That when gametes are formed, the parent separates their two genes that code for the same trait. So the child gets one from each parent.

9. phenotype • the way an organism looks and behaves is called it’s phenotype. • example: what color are your eyes, or your hair? • what you see is the phenotype.

10. Genotype • the gene combination an organism contains is known as genotype.

11. Homozygous vs. Heterozygous • an organism that is homozygous for a trait has two alleles for the trait that are the same. • an organism that is heterozygous for a trait has two different alleles (dominant and recessive).