Transcript 6-1_CFLAEAS493558_U06L05

Unit 6 Lesson 5 Punnett Squares and Pedigrees
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
Florida Benchmarks
• SC.7.L.16.2 Determine the probabilities for
genotype and phenotype combinations using
Punnett Squares and pedigrees.
• MA.6.A.3.6 Construct and analyze tables, graphs,
and equations to describe linear functions and
other simple relations using both common
language and algebraic notation.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
Florida Benchmarks
• LA.6.4.2.2 The student will record information
(e.g., observations, notes, lists, charts, legends)
related to a topic, including visual aids to organize
and record information and include a list of
sources used.
• HE.6.C.1.4 Recognize how heredity can affect
personal health.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
Squared Away
How are Punnett squares used to
predict patterns of heredity?
• One tool for understanding the patterns of
heredity is a diagram called a Punnett square.
• A Punnett square is a graphic used to predict
the possible genotypes of offspring in a given
cross.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How are Punnett squares used to
predict patterns of heredity?
• Each parent has two alleles for a particular gene.
• An offspring receives one allele from each parent.
• Each compartment within the Punnett square
shows an allele combination in a potential
offspring.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How can a Punnett square be used to
make predictions about offspring?
• A Punnett square does not tell you what the exact
results of a cross will be.
• A Punnett square only helps you find the
probability that a certain genotype will occur.
• Probability is the mathematical chance of a
specific outcome in relation to the total number of
possible outcomes.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How can a Punnett square be used to
make predictions about offspring?
• Probability can be expressed in the form of a
ratio, or an expression that compares two
quantities.
• Probability can also be expressed as a percentage.
• A percentage states the number of times a certain
outcome might happen out of 100 chances.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How can a pedigree trace a trait
through generations?
• A pedigree is another tool used to study patterns
of inheritance.
• A pedigree traces the occurrence of a trait
through generations of a family.
• Pedigrees can be useful in tracing sex-linked
disorders, or disorders associated with an allele on
a sex chromosome.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How can a pedigree trace a trait
through generations?
• A woman that is heterozygous for a trait is called
a carrier.
• She is called a carrier because she can pass the
trait to her offspring.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
How can a pedigree trace a trait
through generations?
• Pedigrees can be useful in tracing inherited
disorders such as cystic fibrosis.
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Unit 6 Lesson 5 Punnett Squares and Pedigrees
Saving the European Mouflon
• Scientists use genetics to show how the European
mouflon sheep can be saved from extinction.
• When a population is very small, there is a risk of
too much interbreeding, which can cause harmful
genetic conditions to appear.
• Researchers can identify and breed genetically
dissimilar European mouflons in a laboratory. This
lowers the risk of inherited disorders.
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