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14-1 THE WORK OF GREGOR MENDEL

Objectives Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species. Predict the probability of the

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Page 1: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

14-1 THE WORK OF GREGOR MENDEL

Page 2: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Objectives

Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.

Predict the probability of the occurrence of specific traits, including sex-linked traits, in an offspring by using a monohybrid cross.

Page 3: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Introduction

Can you read the number?

Page 4: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Introduction

Can you read the number?

Page 5: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Introduction

Can you read the number?

Page 6: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Gregor Mendel’s Peas

Austrian monk considered the “father of genetics”.

Genetics – the study of heredity.

Page 7: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Gregor Mendel’s Peas

Noticed pea plants had different traits: Tall vs. short Green vs. yellow

Wanted to figure out why the peas had different traits.

Page 8: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Gregor Mendel’s Peas

Mendel started with pure true-breeding peas. True-breeding – produces identical

offspring. Mendel-cross pollinated peas with different traits. Ex. Tall & short

plants Crossed seven

different traits. Pg. 264

Page 9: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Objectives

Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.

Predict the probability of the occurrence of specific traits, including sex-linked traits, in an offspring by using a monohybrid cross.

Page 10: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Review

Who is this guy? He’s credited with

being the “father of ____.”

What plant did he work with?

Page 11: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Vocabulary

Trait – a specific characteristic. Hybrid – the offspring of crosses

between parents with different traits.

Page 12: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

What Did Mendel Do?

He produced three generations of pea plants.

The original parents were known as the “P (parental) Generation”.

The offspring of the P generation were known as the “F1 Generation”.

The offspring of the F1 generation were known as the “F2 Generation”.

P Generation F1

Generation F2 Generation

Page 13: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

Let’s take pea plant height for example for the P generation…

Page 14: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

The F1 generation was ALL TALL (pg. 265).

Pg. 264

Page 15: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

The F2 generation had three tall plants and one short…

Page 16: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

From this Mendel concluded two things:1) Inheritance is determined by “factors”

passed down generations.

Page 17: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

More Vocabulary

Gene – chemical factors that determine traits.

Allele – different forms of a gene.

Page 18: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

From this Mendel concluded two things:1) Inheritance is determined by “factors”

passed down generations.2) Some alleles are dominant and others

are recessive (principle of dominance).

Page 19: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

How does dominance work???An organism with a dominant allele will

ALWAYS show for that form of the trait. Example: Gene Allele Dominant Allele Recessive Allele

What would this pea plant be…short or tall?

Tt

Page 20: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Genes and Dominance

So…what trait would the following have?

Tt

ttTT

Page 21: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

F2

Segregation

Mendel wanted to what happened to the recessive allele in the F1 cross to produce the F2 generation . F1

Page 22: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Segregation

Segregation – the splitting of alleles during gamete formation.

Segregation – the splitting of alleles during meiosis.

What do we call gamete formation?

Page 23: Objectives  Explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation within a species.  Predict the probability of the

Review and Closure

We’ll talk more about these things later this week.

Have a great Spring Break Come back ready to work on research

project.