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Genetics
Chapter 3 objectives
1.
Discuss the advantages of peas as a genetic model and why Mendel’s
experimental methods were so important to the success of his work.
2.
Be able to explain what a monohybrid cross is and what a dihybrid cross is.
3.
Given an experimental situation:
·
Be able to outline a monohybrid cross or a dihybrid cross, predicting and
solving for the genotypes and phenotypes of all members of each generation.
·
If it is necessary to use a test-cross to solve for genotypes, know what the
appropriate test cross would be.
Be able to draw out the test cross and solve for the genotypes.
·
Be able to use the product law to predict the frequencies of phenotypes.
·
Be able to use a Punnet square in relation to these types of problems.
·
Be able to use the forked-line method to solve experimental problems when
appropriate.
4.
Describe and apply Mendel’s four postulates.
5.
Be able to use pedigree conventions to outline the pedegree of a human
family.
6.
Given a human pedigree, be able to predict the mode of inheritance of a
trait and to predict the genotypes and phenotypes of individuals.
7.
Be able to use and apply the following terms
Parental generation (P1)
First filial generation (F1)
Second filial generation (F2)
Dominant
Recessive
Homozygous
Homozygote
Heterozygous
Heterozygote
Allele
Phenotype
Genotype
True-breeding
Self-fertilizing
Chapter 3 and Class Topics Outline
I.
Observations on heredity made before Mendel’s time (info. isn’t in the textbook)
·
Define
P1, F1 and F2
·
Define
true breeding
o
True
breeding experiments suggested that traits are passed directly from parents to
offspring.
o
·
Define
hybrid and show F1 and F2 from hybrid crosses
o
Contradicted earlier idea that traits passed from parents to offspring
II.
Gregor Mendel and his experimental approach
a.
Why pea plants were a good experimental model
b.
Traits Mendel studied
c.
Mendel’s experimental method
III.
Monohybrid crosses, Mendel’s first three postulates and modern terminology in
relation to Mendel’s terminology
IV.
Punnet Squares
V.
Testcross
VI.
Dihybrid crosses and Mendel’s fourth postulate (independent assortment)
a.
Dihybrid crosses
b.
Independent assortment
c.
Product law of probabilities
d.
Punnet squares for dihybrid crosses
e.
Two character testcrosses
VII.
Trihybrid crosses and beyond
a.
Forked-line method
VIII.
Mendel’s work in relation to what occurs during meiosis (see fig. 3-10)
a.
“Unit factors”, which are what we now call genes, occur in pairs
b.
Segregation of unit factors during the first meiotic division
c.
Independent assortment and genetic variation
IX.
Pedigrees and Human Traits
Back of
chapter “problems and discussion questions” that we will probably do in class.
I recommend that you look at them ahead of class time.
Questions 1, 5, 6, 7, 8, 24, 27a.
Suggested publisher web site “chapter quiz” questions:
1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 17, 18, 20, 21, 22.
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