Objectives 11.1 The Work of Gregor Mendel -Survey Mendel’s studies and conclusions about inheritance. -Examine what happens during segregation.

The scientific study of heredity, known as genetics. What is heredity? The delivery of characteristics from parent to offspring is called heredity. The scientific study of heredity, known as genetics.

The Experiments of Gregor Mendel The modern science of genetics was founded by Gregor Mendel. Mendel used simple garden peas to demonstrate how traits are passed from one generation to the next.

“True Breeding” Self Pollination Pea flowers are normally self-pollinating, which means that sperm cells fertilize egg cells from within the same flower. “True Breeding”

Cross Pollination Mendel decided to “cross” his stocks of true-breeding plants—he caused one plant to reproduce with another plant. The offspring of crosses between parents with different traits are called hybrids.

The Generations When doing genetic crosses, we call the original pair of plants the P, or parental, generation. Their offspring are called the F1, or “first filial,” generation. The offspring of the F1 generation are the F2, or “second filial,” generation.

Genes From these results, Mendel drew two conclusions: 1. An individual’s characteristics are determined by factors that are passed from one generation to the next. Scientists call the factors that are passed from parent to offspring genes.

Alleles The different forms of a gene are called alleles. Each of the traits Mendel studied was controlled by one gene that occurred in two contrasting varieties. The different forms of a gene are called alleles.

Dominant vs Recessive Traits 2. The principle of dominance states that some alleles are dominant and others are recessive. An organism with at least one dominant allele for a trait will exhibit that form of the trait. An organism with a recessive allele for a trait will exhibit that form only when the dominant allele for the trait is not present.

Representing the Gametes A capital letter represents a dominant allele. A lowercase letter represents a recessive allele. THEY MUST ALWAYS BE THE SAME LETTER.

True or False A trait is a specific characteristic that can vary from one individual to another. _________________________

Answers A trait is a specific characteristic that can vary from one individual to another. True