Early Genetics by Emily

Emily Briggs and Annie Rozewski

briggsem — 2015-01-26 16:17:13 UTC

period D

GREGOR MENDEL: THE FATHER OF GENETICS

briggsem — 2015-01-26 16:19:42 UTC

Gregor Mendel was born on July 22nd, 1822 in the Czech Republic. He studied science and mathematics, and worked in a monastery and teaching high school. By working with simple garden peas, Mendel discovered previously unknown information about fertilization, breeding, cross-pollination, and genes.

Peas: A Good Test Organism?

briggsem — 2015-01-26 16:28:52 UTC

Peas were the ideal organism for Mendel's experiment because...

- Peas are small and easy to grow

- They can produce hundreds of offspring

- Experiments could be carried out in just one or two seasons instead of decades

Experiment

briggsem — 2015-01-26 16:36:18 UTC

Before Mendel started his experiment, he needed to know some basic information about fertilization, which is defined as the joining of male and female reproductive cells in order to produce a new cell. For example, he knew that...

-- the female portion of each flower produces reproductive cells called eggs

-- pea flowers are self-pollinating (sperm cells fertilize egg cells from within the same flower)

-- self-polinating meant that offspring would be identical to the original organism (the traits would be the same)

-- cross-pollination produces a plant that has two different parents

Dominant and Recessive Traits

briggsem — 2015-01-26 16:44:43 UTC

Mendel concluded a principle of dominance which states that some alleles are dominant and others are recessive. A dominant trait means that it will appear in the reproduced organism. A recessive trait will only take form if there is not a dominant trait present. For example, in the pea experiment the allele for tall plants was dominant and the allele for short plants was recessive.

P Generation

briggsem — 2015-01-26 16:52:59 UTC

Each original pair of plants is the P (parental) generation. An individual's characteristics are determined by factor that are passed from one parental generation to the next.

F1

briggsem — 2015-01-26 16:55:59 UTC

The offspring of the parental generation is called the first filial (F1) generation. In Mendel's experiment, he discovered that each F1 plant produces of gametes, one with the allele for tallness and one with the allele for shortness.

F2

briggsem — 2015-01-26 16:57:42 UTC

An F1 cross will produce the second filial generation. The traits controlled by the recessive alleles reappear in the second generation.