Part 2: Heredity and

Mendelian Genetics

The Genetics of Inheritance

Traits – _______________________

_____________________________.

Ex. Earlobes, Dimples, Curved

Fingers, Rolling Tongue

Inheritance – The mechanism

that _______________

___________________ between

generations.

Genetics – The branch of biology that

deals with the _________________

_____________________________

Farmers knew about ______________

________________before these

principles were scientifically proven.

People have been ________________

domesticated __________________ for

millennia.

The __________________of how

these processes occurred were

unknown.

The Greek philosophers:

____________, 460-377 B.C.E.,

suggested that the body produced

“__________” and that these seeds _____

to give rise to a _________________.

A few theories arose…

__________, 384-322 B.C.E.,

proposed that ________________

mixed upon conception.

In the 1500’s, English physician,

_______________ theorized that a

process called __________was how

inheritance occurred. A process based

upon the development of the ________

_____________, and affected by

___________________________ the

mother.

Dutch Scientist and Microscopist, ______

_________________, used a microscope

in the mid to late 1600’s to examine the

__________________and other animals.

Leeuwenhoek later proposed that the

male sperm actually contained ____

______________ which would later be

_____________ in the mother’s uterus.

Preformation

Theory

Sperm and Egg at Conception

Charles Darwin suggested, in the mid 1800’s

that children had characteristics that were

___________________________ , but he

was unable to explain the _______________.

The answer to ________________ came

from Darwin’s contemporary ___________

Mendel’s Contributions

“The Father of Modern

Genetics”

Gregor Mendel 1822-1884

The Inheritance of One Trait

Gregor Mendel, an Austrian monk,

studied the ____________________

using the common _________________

as an experimental model.

Prior to Mendel’s work at the Monastery of

St. Thomas in Brunn, he attended the

University of __________.

While at the University, his studies

included ___________________ –

training that would later prove to be

invaluable.

Why did Mendel choose the

pea plant (Pisum sativum) as

an experimental model for his

study?

The position of the _____________ of the

plant are entirely __________________;

this allowed Mendel control over ______

_______________________.

The plants exhibited ____________

___________________between

generations. Each trait had only ______

________________________________.

How did Mendel set up his

experiment?

The first thing he did was _________

______________________ for each of

the traits he wished to study.

This process ensured he was working with

plants that ____________________.

i.e. the plants produced __________

__________ when any _________of the

same _____________were bred together.

Mendel prepared a __________ for each

of the ___________ he studied.

Each of these ___________were easily

identified in the _______________ of the

offspring generation.

The seven traits were:

Before we jump in:

- Solving genetics problems involves an

____________________ (the measure of

how likely an event is).

Complete the following:

Mathematically

To determine probabiliy:

# of ways an event can occur

Total # of Outcomes

=

A Monohybrid Cross

Mendel’s first experiment involved the

________________________________

___________________. Mendel called

this the ________________________.

From this cross, the offspring were

referred to as the _________________

These were called _________ because

they resulted from the ______________

________________________________.

This type of cross is called ________

because only ___________________,

was involved.

A monohybrid cross…

____________

____________

__________________

__________________

__________________

_________________

_________________

_________________

_________________

_________________

The results of the experiment

Mendel’s first experiment showed that a

_________________________________

________________________. That is, all

of the ____________________________.

This led Mendel to conclude that the trait

for _________________________over

the _____________________________.

Dominant & Recessive Traits

Dominant Trait – a characteristic that is

__________________________. Only

_______________________ must be

present for the _____________to be

expressed.

Recessive Trait – a trait that is ________

______________________ that code for

the ___________________are present.

In Mendel’s experiments, he found that one

__________________________________

__________________________________.

Mendel’s Principle of

Dominance

When ________________________

______________, the offspring will

only express the _______________

_____________________________.

Back to Exp. 1 – Monohybrid Cross

Punnett

Square Tall Plant

T T

Short

Plant t

t

Mendel’s next experiment involved the

crossing of ___________________

__________________. He allowed the

__________________________ to

undergo ____________________.

Exp. 2 – Monohybrid Cross with F1

Offspring

Punnett

Square Tall Plant

T t

Tall

Plant T

t

This produced a ________________, that

Mendel called the ___________. ________

of plants in the F2 generation were ________

_______________________

This ratio of _____ has become known as the

________________________.

Mendel drew four conclusions from his

experiments:

Each parent in the F1 generation

begins with __________________.

Individual ______________________

_______________________________

The factors are ________________

and each ___________________ factor

to each _____________.

Each offspring ________________ from each

parent. If the ___________________ by the

offspring, it will be _____________; even if the

____________________________.

The recessive factor will _________________

_____________________________________

.

The Law of Segregation

Inherited traits are ________________

___________. These factors _________

____________ when the _________ are

formed. One factor from __________

______________ in each gamete.

F1 Hybrid Cross (Showing

Segregation)

What are “factors”?

We now know that Mendel’s factors _____

________. A _____ can occur in _______

_________________________________

When _____________ are present, a

_____________________ and the

_____________ is not. Each of these

__________ will pass on to the ______

___________ where they may or may not

__________________.

The arrangement of alleles.

Alleles can be identified by using a

________________________________.

i.e.

The ________________usually determines the letters

of the _____________________for the code. For

example the ___________________would be ____,

with both ________________________for a

dominant trait. The code for a __________________.

If the code read ____, it should be

understood that this individual would be

________________________________

________________________________.

The arrangement in which both alleles

are represented by the ______________

______________________________

To clarify, one must indicate the organism

as being either ____________________

_________________________________

_________________________________

The arrangement in which both alleles

are represented by _______________

________________________________

The following terms will help you read

about and describe heredity:

________________________________

________________________________

________________________________

________________________________

A tall-stem pea plant could have two

_____________________________.

A short-stem pea plant can have only

___________________ since the

allele for ________________________

________________________________

Phenotype refers to the

_____________________________.

Since a pea plant can be tall or

short, there are _______________

______________________________.

The tall phenotype may have _____

______________________________

Sample Problem 1

Consider a cross between a pea plant that is heterozygous

for round seeds and a pea plant that has wrinkled seeds.

Determine the genotypes of the possible offspring.

Sample Problem 2

A plant that is homozygous for purple flowers is

crossed with a plant that has white flowers. If the

purple condition is dominant over the white

condition, what are the genotypes and

phenotypes of the F1 generation?

Sample Problem 3

Determine the genotypes of the parents if the following

offspring are produced.