father of geneticsfather of genetics

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Austria

Italy

Johann MendelJohann Mendel

Germany

Poland

Austria

Czech Republic

was born in 1822 in Heinzendorf, Austria, to a peasant farming family.He was an Austrian Monk with a love of science.

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During his early years at the monastery, Mendel began studying and breeding

mice.The

bishop was not

pleased.

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Brother Gregor settled on bees . . .

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and peas.

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Mendel narrowed his focus to one

particular garden pea, Pisum sativm.

Mendel continued to conduct numerous

experiments on plants.

For 8 years, Mendel experimented with over 28,000 peas in the large gardens attached to the

monastery.

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Rather than study every characteristic of the garden pea, Mendel

narrowed his observations to 7 traits.

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Garden Pea Traits Observed

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smooth wrinkled

yellow green

inflated constricted

green yellow

purple white

axial terminal

tall short

Seed shape

Seed color

Pod shape

Flower color

Flower location

Plant size

Pod color

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In 1866 when Mendel was 44, his experimental results were

published

. . . and ignored long after he died.

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Alleles: the different forms of a trait a gene may

have

You get ONE allele from each

parent

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Examples in pea plants:

-short or tall plants-red or white flowers-green or yellow peas

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Alleles:

can be1. Dominant-meaning they

cover up the other alleles or they can be

2. Recessive –meaning they can be covered up or can

seem to disappear

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DOMINANT alleles:

written in CAPITAL LETTERS

recessive alleles: written in lower case letters

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If the alleles are the same they are called homozygous (also known as purebred).

Example: TT or tt (both parents gave the same allele)

If the alleles are different they are called heterozygous (also

known as hybrid).Example: Tt (parents gave

different alleles)

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Genotype vs. PhenotypeThe genotype of an

organism is its genetic makeup

Example: TT=homozygous

dominantTt=homozygous

recessiveTt=heterozygous

The phenotype of an organism is the way the organism looks and/or behaves (what you see)

Example: short, blue eyes, brown hair, etc…

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For the recessive allele or form of a trait to be seen, the

genotype must be homozygous recessive

tt phenotype=short

The dominant form will show either homozygous dominant

OR heterozygous TT and Tt phenotype=tall

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Punnett squareA punnett square is: a simple chart for predicting the results

of a cross.

It shows the _________: the genetic makeup of an organism and the

________: the way an organism looks or behaves

genotypephenotype