Transcript Chapter 5: Heredity Section1- Genetics

Chapter 4
Part 2- Genetics Since
Mendel
Life Science
Question…

If you crossed Purebred Red fouro’clock plants with Purebred White
four-o’clock plants, what would the
offspring look like?

Remember… they were Pink !?!?!
 Incomplete
Dominance- when
two homozygous parents
combine, the offspring results in a
mixed (or blended) phenotype
 The
evil Grey chicken!?!?!
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When neither allele for a trait is
Dominant.

The phenotype produced is a blending
between the two homozygous parents.
– The combining of Purebred Red &
Purebred White produced PINK plants.

Although Mendel studied peas that
were controlled by two alleles, many
traits can be controlled by more than
two alleles…
Multiple Alleles

A trait that is controlled by Having
more than two alleles is controlled by
Multiple Alleles.

Traits controlled by Multiple Alleles
produce more than three phenotypes
of that trait.
Example of Multiple
Alleles…

Blood Types: A, B, AB, and O.
– The O allele is recessive to both A and B
Other Worksheet…
Phenotype:
 A 
Genotype:
AA or Ao Genotype

B–
BB or Bo Genotype
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AB –
AB Genotype

O–
oo Genotype
A and B are _______________ alleles
 o is _________________
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
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
“A Blood” you need _____ and _____
_____ and _____
“B Blood” you need _____ and _____
_____ and _____
“AB Blood” you need _____ and _____
shows______________
“o Blood” you need _____ and _____
Because it’s ___________
Polygenic Inheritance

Polygenic Inheritance- when a group
of gene pairs acts together to produce
one trait.
– Which creates more variety in
phenotypes
What would be an example?
 Many traits such as…Eye Color, Hair
Color, Skin tone, & Handspan are
traits produced by a combination of
genes.

Human Genes &
Mutations

What are Mutations?!?!?
Mutations
 Mutations
- a permanent
change in the DNA sequence
A
mutation can be harmful,
beneficial, or cause no effect.
Chromosome Disorder
 Chromosome
disorders- caused
by more or fewer chromosomes
than normal
–Downs Syndrome- caused by
an extra chromosome (trisomy)
at Chromosome 21
Recessive Genetic
Disorders

Recessive Genetic Disorders are
disorders passed through the
Recessive alleles.

Both parents contain the recessive
allele (containing the disorder) that
comes together in the offspring.
 When
both parents are
Heterozygous, they do not show
any symptoms
– (Called “carriers” for the trait.)

Example- Cystic Fibrosis is a
homozygous recessive disorder.
Sex-Linked Disorders

An allele inherited on a sex
chromosomes ( X or Y ) is called a
sex-linked gene.

Inherited conditions are linked with the
X and Y chromosomes.

Example- Color Blindness and
Hemophilia

Pedigree- used to follow or trace traits
through generations of a family.
Section 3
III.
Advances in Genetics
A. Genetic Engineeringexperimentations that changes the
arrangement of DNA that makes up
a gene.
Types:
1.
Recombinant DNA

Inserting a useful section of DNA into
a bacteria

Example- Creating Insulin (Page
143)
2.
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Gene TherapyWhen a “normal allele” is placed into
a virus, the virus then delivers the
normal allele when it infects a
specific cell. (Figure 13 Page 144)
May be used to control Cystic
Fibrosis and other disorders.
3.
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Genetically Engineering PlantsPlants are created by genetically inserting
the desired genes of one plant into
another plant you want to show those
genes.
Also genetically engineered: ANIMALS

“Cloning”