Chapter 11: The Beginnings of Genetics
What is Heredity?
The passing of characteristics (traits) from parents to offspring
Genetics is the study of heredity
A famous guy…. Aka “The Father of Genetics”
George Mandel
o The first person to conduct carefully planned experiments
and accurately record the results in the field of genetics
Introduction- Gregor Mendel
Father of classical genetics
Born Johan Mendel in 1822 to peasant family in the Czech
village of Heinzendorf part of the Austro-Hungarian empire at the
time.
Austrian Augustinian monk (Actually from Brunn which is now the
Czech Republic
Mendel’s Ideas….
Before starting his work, Mendel had some ideas about how
heredity might work
He made some hypotheses (guesses based on what he knew)
o There are elements that are passed from parent to
offspring
o Different elements control different traits
o Elements remain unchanged during the organism’s life
o Elements are passed on through gametes (sex cells)
The subject of Mendel’s experiments….. pea plants
, Why use Pea Plants?
Pea plants have several traits expressed in only 2 forms
Eg’s
o Seed shape smooth or wrinkled
o Seed color yellow or green
o Stem height tall or short
o Pod color yellow or green
Why Peas?
Pea flowers are constructed in such a way that they typically
self-fertilize
Because of this, it is relatively easy to control crosses in peas
His Experiments….
First, he allowed all the plants to self-fertilize
o This made pure lines of various traits
Then he began crossing the pure lines
o This is called hybridization
An Example…
Height
o He made pure lines of tall and short plants
o He then crossed a tall plant with a short plant
o The new plant is a hybrid
What did he find?
The first generation (f1) contains all tall plants
Then he crossed a tall f1 plant with another f1 plant….
o What do you think happened??
2
What is Heredity?
The passing of characteristics (traits) from parents to offspring
Genetics is the study of heredity
A famous guy…. Aka “The Father of Genetics”
George Mandel
o The first person to conduct carefully planned experiments
and accurately record the results in the field of genetics
Introduction- Gregor Mendel
Father of classical genetics
Born Johan Mendel in 1822 to peasant family in the Czech
village of Heinzendorf part of the Austro-Hungarian empire at the
time.
Austrian Augustinian monk (Actually from Brunn which is now the
Czech Republic
Mendel’s Ideas….
Before starting his work, Mendel had some ideas about how
heredity might work
He made some hypotheses (guesses based on what he knew)
o There are elements that are passed from parent to
offspring
o Different elements control different traits
o Elements remain unchanged during the organism’s life
o Elements are passed on through gametes (sex cells)
The subject of Mendel’s experiments….. pea plants
, Why use Pea Plants?
Pea plants have several traits expressed in only 2 forms
Eg’s
o Seed shape smooth or wrinkled
o Seed color yellow or green
o Stem height tall or short
o Pod color yellow or green
Why Peas?
Pea flowers are constructed in such a way that they typically
self-fertilize
Because of this, it is relatively easy to control crosses in peas
His Experiments….
First, he allowed all the plants to self-fertilize
o This made pure lines of various traits
Then he began crossing the pure lines
o This is called hybridization
An Example…
Height
o He made pure lines of tall and short plants
o He then crossed a tall plant with a short plant
o The new plant is a hybrid
What did he find?
The first generation (f1) contains all tall plants
Then he crossed a tall f1 plant with another f1 plant….
o What do you think happened??
2
