objectives explain how genotypes (heterozygous and homozygous) contribute to phenotypic variation...
TRANSCRIPT
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 occurrence of specific traits, including sex-linked traits, in an offspring by using a monohybrid cross.
Introduction
Can you read the number?
Introduction
Can you read the number?
Introduction
Can you read the number?
Gregor Mendel’s Peas
Austrian monk considered the “father of genetics”.
Genetics – the study of heredity.
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.
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
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.
Review
Who is this guy? He’s credited with
being the “father of ____.”
What plant did he work with?
Vocabulary
Trait – a specific characteristic. Hybrid – the offspring of crosses
between parents with different traits.
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
Genes and Dominance
Let’s take pea plant height for example for the P generation…
Genes and Dominance
The F1 generation was ALL TALL (pg. 265).
Pg. 264
Genes and Dominance
The F2 generation had three tall plants and one short…
Genes and Dominance
From this Mendel concluded two things:1) Inheritance is determined by “factors”
passed down generations.
More Vocabulary
Gene – chemical factors that determine traits.
Allele – different forms of a gene.
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).
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
Genes and Dominance
So…what trait would the following have?
Tt
ttTT
F2
Segregation
Mendel wanted to what happened to the recessive allele in the F1 cross to produce the F2 generation . F1
Segregation
Segregation – the splitting of alleles during gamete formation.
Segregation – the splitting of alleles during meiosis.
What do we call gamete formation?
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.