Download Introduction to Genetics

Introduction to
Genetics
It all started here
The Beginnings of genetics
Questions:
Who is the
father of
genetics?
What is
genetics?

Genetics - is the study of
heredity
or the study of passing of traits
from parent to offspring
* The father was Gregor
Mendel
HE.912.C.1.4 Analyze how heredity and family history impact health
What was known?
Questions:
Explain the types of
chromosomes
and their
importance.
What is the
importance of
meiosis?
Why is fertilization
important?

Chromosomes determine
everything about living things
 Come
in pairs
 During meiosis they segregate to
make a gamete (egg or sperm)
 Fertilization - pairs the
chromosomes again
 The 2 types are autosomes and
sex chromosomes
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
SC.912.L.16.17 Compare mitosis and meiosis and relate to the process of sexual and asexual reproduction and
their consequences for genetic variations.
HE.912.C.1.4 Analyze how heredity and family history impact health
When fertilization occurs …
Each parent gives one of each pair of chromosomes
Importance of segregation
Questions:
 Without segregation an
What is
offspring will not get the
segregation
correct
number
of
and why is it
chromosomes – resulting in
so important?
mutations or death
 Too

many is called polyploidy
Example: Down syndrome - extra
21st chromosome
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
HE.912.C.1.4 Analyze how heredity and family history impact health
Extra 21
Extra 13
Mendel’s Discoveries
Questions:
What is the
difference
between a
gene and
allele?
What 2 forms
can alleles
take?

On chromosome are genes
 They

determine a specific trait
Gene have different forms
called alleles
 Dominant
alleles - strong
(shown with a capital letter)
 Recessive alleles - weaker
(shown with a lower case letter)
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
HE.912.C.1.4 Analyze how heredity and family history impact health
Importance of alleles
Questions:
What is the
difference
between the
genotype and
phenotype?

Typically there are 2 alleles
that represent each trait
 This two letter combination
is called the genotype
 TT or
Tt or tt
 We use the genotype to
determine what it looks like
– called the phenotype
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
Determining what the trait looks like
Questions:
What is the
difference
between a
dominant and
recessive
trait?

Dominant traits - are always
seen
 RR
and Rr both will show the
dominant trait

Recessive traits – only seen
if there are no dominants
present
 rr
will show the recessive trait
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
HE.912.C.1.4 Analyze how heredity and family history impact health
Determining what the trait looks like

Codominance both traits are
seen
 Example:
multicolored
shells or cats
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
Determining what the trait looks like
Questions:
What is the
difference
between
codominance
and
incomplete
dominance?

Incomplete dominance –
none are dominant so they
mix
Example: red flower plus
white flower = pink flower
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
Determining what the trait looks like
Questions:
Explain what
multiple
alleles means
and explain
an example.

Multiple alleles – when
there are more than 2
alleles that control the trait


But still only 2 letters in the
genotype
Blood type has A B and O
 A blood type: XAXA or
XAXO
 B blood type: XBXB or
XBXO
 AB blood type: XAXB
 O blood type: XOXO
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
HE.912.C.1.4 Analyze how heredity and family history impact health
Determining what the trait looks like
Questions:
What is a
polygenic trait
and why does
it allow for so
much
diversity?

Polygenic traits – have
more than 2 genes for a
trait that all effect the
outcome
 The
genotype has more
than 2 letters (AAbbCc)
 Example - skin color, hair
color, height
SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including
dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
Determining the possibilities
Questions:
What is
probability
and how is it
used in
determining
the possible
genetic
outcomes?



Probability – is the likelihood
an event will occur
In genetics the Punnett
square is diagram used to
determine the genetic
probability of an offspring
It tells you what the parents
have, what the children could
have, but it never tells you
the actual outcome
SC.912.L.15.15 Describe how mutations and genetic recombination increase genetic variation.
Using the Punnett Square
Questions:
What is the
difference
between
homozygous
and
heterozygous?
Why do you need
to know the
parent
genotypes first?

First - determine the
genotypes both parents
 Homozygous
dominant both letters are capital
 Homozygous recessive both letters are lower case
 Heterozygous - one letter
is capital and the other is
lower case
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
Step 2: Fill in the square
If B=brown eyes and b=blue eyes
Cross a homozygous dominant and a homozygous
recessive individual
b
B
B
Bb
Bb
Bb
Bb
b
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
Interpreting the Punnett Square
Questions:
How do you find
ratios and
percentages
for the
Punnett
square?

Ratios
 Go
from most dominant to
most recessive
 Include genotypic ratios
 Include phenotypic ratios
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
What if we look at more than one trait?
Questions:
What does the
principle of
independent
assortment
state?
Why is this idea
important?

Follow the Principle of
independent assortment –
says that genes for different
traits segregate independently
other words – each parent will
give one of each letter to the
offspring
 In

Example: RrYy
 Possibilities
alleles passed are
RY Ry rY ry
SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
Genetic disorders
Questions:
What is a
dominant
disorder and
why is it so
dangerous?

Dominant disorders – on
the dominant genes
 All
it takes is one bad gene
and you have it
 Example: Achondroplasion dwarfism
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
HE.912.C.1.4 Analyze how heredity and family history impact health
Dwarfism
Primordial Dwarfism
Genetic disorders
Questions:
What are
recessive
disorders?
Why is being a
carrier still
dangerous?

Recessive disorders – are
on the recessive alleles
 If
you have 2 recessive you
have it
 If you have 1 you are a
carrier
 Example:
Cystic Fibrosis – mucus in
lungs
 Albinism – no melanin

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
HE.912.C.1.4 Analyze how heredity and family history impact health
Albinism
Genetic disorders
Questions:
Why is it more
dangerous for
boys than
girls when it
comes to sex
linked
disorders?

Sex linked disorders – on the
X and Y chromosomes
 If
it is on the X


 If
Females – both parent must give it
Males – only mom gives it
it is on the y


Females – don’t get because no y
Males – if dad has it all sons have it
 Examples on X:
 Baldness – loosing hair
 Hemophilia – blood can’t clot properly
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
HE.912.C.1.4 Analyze how heredity and family history impact health
Baldness
Color Blindness
http://www.kcl.ac.uk/teares/gktvc/vc/lt/colourblindness/cblind.htm
http://webexhibits.org/causesofcolor/2.html#vissamp
Genes affected by the environment
Questions:
 Characteristics can be
How can
affected by the environment
environmental
 Examples:
factors affect
 Nutrition affects height
characteristics?
 Scholastic verses nonscholastic home affect
intelligence
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
Why organisms naturally different
Questions:
Explain
organisms
naturally
differ?
Crossing over
 Independendant
assortment
 Mutations

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
HE.912.C.1.4 Analyze how heredity and family history impact health
How humans cause variations?
Questions:
Explain how
man has
caused
genetic
difference in
organisms.





Mutations – environmental or
chemical
Hybridization – crossing 2 dissimilar
organisms
Selective breeding – crossing 2 of
same species
Inbreeding – crossing organisms in
the same family tree
Genetic engineering - the process of
man reading, editing, and reinserting
pieces of DNA
SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health
from the perspectives of both the individual and public health.
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including
medical and ethical issues.
1. Extract DNA
2. Read the
Sequence
3. Cutting the
DNA
4. Separating
DNA – using
electrophoresis
5. Pasting –
using enzymes
6. Making Copies
Cell Transformation in Bacteria
Questions:
Explain how
man has
caused
genetic
difference
in
organisms.


Cell transformation - process of
taking DNA from one cell into
another cell
They use bacteria
 Foreign DNA is joined to a
circular DNA called a plasmid
 Plasmid is mixed with bacteria
 Treated with anti-bacteria to
kill all cell except those with
the new gene
SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.
SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including
medical and ethical issues.
Using Bacteria For Genetic Engineering