Non-Mendelian-Genetics Patterns of Inheritance.ppt

Non-Mendelian-Genetics

1. Non-Mendelian
Genetics
Inheritance Concepts Mendel Never Imagined!

2. Incomplete Dominance
The hybrid (heterozygous) offspring displays a
THIRD Phenotype!! Neither trait is completely
dominant, as a result, there appears to be a blending
phenotype.
Red FlowerRed Flower X White Flower = PinkPink
(RR) (WW) (RW)

3. Incomplete Inheritance Problem
What is the probability of pink flowers if pink
flowers are bred with red flowers?
50%
chance
of Pink
Flowers

4. Incomplete Inheritance Problem
What is the probability of white flowers if pink
flowers are bred with pink flowers?
R w
R RR RW
W RW WW

6. Sample problem:
Red snapdragon flowers (R) are incompletely
dominant to white snapdragon flowers (r).
A heterozygous flower is crossed with a white flower.
What is the genotypic and phenotypic ratios of the
offspring?

7. Codominance
Both traits are dominant, and show up in the phenotype
together. Co means “together”
Black Cow Black Cow X White Cow = Sppottteed C Coww

(BB) (WW) (BW)

8. CODOMINANCE
-BOTH THE DOMINANT ALLELES ARE
EXPRESSED IN THE HETEROZYGOUS
INDIVIDUAL.
-USE 2 DIFFERENT CAPITAL LETTERS TO
RERESENT THE DOMINANT ALLELES

9. Co-dominance
•Examples: blood types and fur coat colors
•alleles I
A
and I
B
are both dominant and can be expressed: AB blood type
•Roan cows: red and white coats
•Chickens: black and white feathers

10. Codominance Examples
Roan cow: both red and white
AB blood group

11. CoDominance Problem
What are all the possible phenotypes when two
spotted cows are bred?
Possible
phenotypes
are a black
cow, 2
spotted
cows, and a
white cow

12. Sample problem:
Red and white coat color are co-dominant in cattle.
Two heterozygous cows are crossed. What is the
genotypic and phenotypic ratio of the offspring?

13. 3.Multiple alleles – trait is controlled by more than two alleles , so
there are more than two possible phenotypes.
3.Polygenic traits – These traits are controlled by more than one
gene and show a wide range of phenotypes. Ex. Human
height, skin color.
Remember that environment can also play a role
in the expression of a trait!

14. MULTIPLE ALLELES
Several dominant alleles and/or recessive alleles can be
combined to create multiple phenotypes.

15. Multiple Alleles
When more than 2 varieties exist in a trait. Many animals have a
variety of coat colors.

16. Multiple-Allele Series
•More than two choices of alleles are present for a trait
•ABO blood type has three alleles
•ABO Blood types:
•If both A and B are present, type is AB
•Neither is recessive
•Individuals can be type A, B, AB, or O (recessive)

17. Multiple AllelesMultiple Alleles

18. What is blood made up of?
•The red blood cells
•contain hemoglobin.
•Red blood cells transport O
2
and CO
2
to and from body
tissues.
•The white blood cells
• fight infection.
•The platelets
• help the blood to clot
•The plasma
•Fluid which contains salts and various kinds of proteins.

19. Determining Blood Type
•Protein molecules found on the surface of RBC’s and in the
blood plasma determine the blood type of an individual.
•Antigens are located on the surface of the red blood cells
•Antibodies are in the blood plasma.


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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20. What are the different blood
groups?
•Blood group A (I
A
, I
A
), (I
A
, i)

have A antigens on the surface of red blood
cells and B antibodies in blood plasma.
•Blood group B (I
B
, I
B
), (I
B
, i)

have B antigens on the surface of red blood
cells and A antibodies in blood plasma.

21. What are the different blood
groups?
•Blood group AB (I
A
, I
B
)

have both A and B antigens on the surface
of red blood cells and no A or B antibodies
in blood plasma.
•Blood group O (i, i)
have neither A or B antigens on the surface
of red blood cells but have both A and B
antibodies in blood plasma.

22. Blood Type
In human blood, type A blood and type B blood are
codominant. However, there is a recessive allele for
type O.
Type A and B show regular dominance over this
recessive allele. Thus, the only way to be type O is to
be homozygous recessive.

23. Blood Type Inheritance Rules:
1.A person with the I
A
allele
will have A carbohydrates.
2.A person with the I
B
allele
will have B carbohydrates.
3.A person with the recessive i
allele will have no
carbohydrates.
4.Or a person with both I
A
and
I
B
alleles will have both A and
B carbohydrates on their cells.
Cells Genotypes Blood types
I
A
i, I
A
I
A
Type A
blood
I
B
i, I
B
I
B
Type B
blood
I
A
I
B
Type AB
blood
ii
Type O
blood

24. Blood Type Problems
If a woman with AB blood
has children with a man
who has type O, what will
be the possible genotypes
of their children? What will
be their blood types?
I
A
I
B
i
i
I
A
i
I
A
i
I
B
i
I
B
i

25. Blood Type Problems
Blood Type Problem 2: A
woman with type B blood
has a child with type O
blood. How is this possible
if her husband has type A
blood?

26. Blood transfusions – who can
receive blood from whom?
•The transfusion will work if a person who is going to
receive blood has a blood group that doesn't have
any antibodies against the donor blood's antigens.

27. • People with blood group 0 are called
"universal donors" and people with blood
group AB are called "universal receivers."

28. Rh Factor
•Refers to another antigen on red blood cells
•Dominant trait is to have the antigen
•Rh
+

•Recessive trait is not to have it
•Rh
-

•A person with Rh
-
blood will produce
antibodies to Rh
+
blood
•Can be a problem in pregnancy

29. Punnett practicePunnett practice
•Give the genotypic and phenotypic ratio of the
potential children of a couple, if the man is
heterozygous A-type blood and his wife is
heterozygous B-type blood.

30. Blood Typing Punnetts:
 
Blood Types: A, B, AB, and O
 
Genotypes:

I
A
I
A


I
B
I
B


I
A
i

I
A
I
B


I
B
i

i
i
 Practice
Problem 1: A man of blood type AB marries a woman of blood type A. What are the
possible
blood types of their offspring if the woman’s mother was blood type O?
 
 
 
 
 
 
Practice
Problem 2: A child with blood type O has a mother with blood type A and a father with
blood
type B. The parental genotypes for blood types must be?
What
are the possible blood types of their offspring?

31. Sample Problem #1:
Adam Sandler is homozygous for type A blood. Megan Fox
is heterozygous for type B. If they have kids what will be
the genotypic and phenotypic ratios of the possible kids?

32. Sample Problem #2:
Jimmy Fallon has type O blood. Jennifer Aniston
has type AB blood. If they have kids what will be
the genotypic and phenotypic ratios of the possible
kids?

33. Sample Problem #3:
Channing Tatum has type A blood. Ms. Palmeri has
type B blood. They have a baby with type O blood.
How is this possible? Show your work!

36. Sex-linked Inheritance
Genes for some traits are found on the sex
chromosomes (X or Y)
Most of these traits are recessive the normal gene is
dominant
•Heterozygous Females (XXHeterozygous Females (XX
cc
) ) are carrierscarriers. They do not
show the trait, but carry a gene for the trait.
•Homozygous Females (XHomozygous Females (X
cc
XX
cc
) ) have the trait
•Males with the gene (XMales with the gene (X
cc
Y) Y) have the trait.—.—They do not
have another X to counterbalance the affected gene

37. Color blindness is a sex-linked recessive
trait. The gene for this trait is inherited
through the X chromosome.
If a woman with normal vision
has children with a man
who is colorblind,
what are the chances
that their children will be
colorblind?
Will any children be carriers
of the trait?
X
c
Y
X
X
XX
c
XX
c
XY
XY

38. Are they controlled by both sex
chromosomes?
•Most sex-linked traits are controlled by genes on the X
chromosome.
•This is because an X chromosome is much larger than a
Y chromosome.
•A few traits are suspected to be controlled by genes on
the Y chromosome, however there is less research about
Y-linked traits.

39. Different Forms of Sex-linked Inheritance
•There are three different forms of sex-linked inheritance that
we will be examining:
•X-linked recessive inheritance
•X-linked dominant inheritance
•Y-linked inheritance

40. X-linked Recessive Inheritance
•X-linked recessive traits are traits resulting from a
recessive allele on the X chromosome.
•There are over 100 different human conditions that are
caused by recessive alleles found on the X chromosomes.
•X-linked recessive alleles are represented by a X ,
superscript lower case letter

41. X-linked Recessive Inheritance
•These traits tend to show up in males more than females.
•Why?

42. XO Turner’s syndrome
-a. appear as a female phenotypically
-b. the female pattern is the default pattern set to
develop as female unless something triggers a change-
-c. but doesn’t develop into the adult pattern
-d. hips and breasts remain immature
-e. no Barr bodies
-f. mental function is not impaired
-g. 1/5000 affected
-h. approximately 15-20% of aborted fetuses

43. X-linked Dominant Inheritance
•X-linked dominant traits are traits that result from the
presence of a dominant allele on the X chromosome.
•Unlike X-linked recessive traits, females and males
both require only ONE dominant allele in order to
express the trait.
•X-linked dominant traits are represented by an X,
superscript capital letter or a (+)

44. Polygenic Traits
Require more than one gene (allele) to determine trait.
Skin tone is determined by 4-6 genes—that means that there may
be six different chromosomes involved!

45. Polygenic Traits
•Most of your traits are controlled by the interaction of many
genes.
•Multiple genes working together produce a continuous
distribution in a “Bell Shape” curve of degrees.

46. Examples of Polygenic Traits
•Body Type
•Height
•Skin Color
•Hair color
•Eye color
•Intelligence
•We often see the famous
“Bell Curve”
Individual genes of a
polygenic trait follow
Mendel's laws but
together do not produce
Mendelian ratios.

48. Non-Mendelian Genetics
What are the similarities and differences
between each of these forms of inheritance?
How will you remember? What are
examples of each type?
Incomplete inheritance
CoDominance
Multiple Alleles
Polygenic Traits
Sex-linked inheritance

49. The Environment
The Environment
Heavily Influences
Heavily Influences
Polygenic traits
Polygenic traits

50. Environmental Factors
•Mendel stated that genes will predict traits (phenotypes) not the environment
•Today: phenotypes can be influenced by the environment
•Example: hydrangea plant
•Acidic soil: flowers are blue
•Basic soil: flowers are red
•Example: artic fox
•Temperature: warmer-more enzyme production- darker coat
•Cooler: less enzyme production- white coatwhite coat
•Example: human height/skin color
•Nutrition and height
•Uv rays and skin color

51. Recent studies show …
•Hypertension
•Diabetes
•Cancers
•Allergies
•Cardiovascular diseases
•Behavioral traits (alcoholism and phobias)
…..have some genetic link but also environmental explanation.