Non-Mendelian Genetics: Genetics that don

1
Non-Mendelian GeneticsGenetics that dont
follow Mendels laws
2
Vocabulary Terms

• 93. Pedigree
• 94. Sex-linked trait
• 95. Polygenic trait
• 96. Incomplete dominance
• 97. Codominance
• 98. Multiple alleles
• 99. Mutation

Read 171-180
3
Chromosomes and Human Genetics

• 2 Types of Human Chromosomes
• Sex Chromosomes- Determine the sex of the
  individual as well as other traits. Diploid cells
  have 1 pair of these.
• Male- XY (not the same size but are homologous
  partners during meiosis).
• Female- XX
• Autosomes- Contain genes unrelated to the sex of
  the individual. Diploid cells have 22 pairs of
  these.

4
Determining Sex
MOM
X
X
X
X
X
X
X
DAD
X
Y
X
Y
Y
5
Sex-Linked TraitsGenes on the Sex Chromosomes

• Expression of certain genes often appears more in
  one sex than the other
• Males have 1 x sex chromosome therefore, it
  only takes that one x to be affected to make the
  male have a x-linked disease
• X linked disorders show up in males whose mothers
  were carriers (heterozygotes)
• X-linked disorders show up rarely in females
• See Royal Families of Europe Pedigree
• Ex. Eye color in fruit flies, hemophilia,
  color-blindness

6
Colorblindness Tests
7
(No Transcript)
8
Practice Sex-linked Problems

• Hemophilia is a recessive trait linked to the x
  sex chromosome. What will the result be of
  mating between a carrier female and a normal male?

9

• Red-green colorblindness is a recessive trait
  linked to the x sex chromosome. A colorblind
  female and a normal male have a child. What is
  the probability that it will be colorblind?

10

• 4. Muscular Dystrophy is an X-linked recessive
  trait. A carrier female and a normal male have
  children. Will any of their children have a
  chance of having this disorder? If so, who?
  Show your work.

11

• NOT IN YOUR NOTES BUT GIVE IT A TRY!
• Hemophilia is inherited as an X-linked recessive.
  A woman has a brother with this defect and a
  mother and father who are phenotypically normal.
  What is the probability that this woman will be a
  carrier if she herself is phenotypically normal?

12
Pedigree chart showing family genetic
relationships
13
Pedigree Analysis

• Method of tracking a trait through generations
  within a family.
• Good method of tracking sex-linked traits as well
  as autosomal traits.

14
Click and choose the button
15
(No Transcript)
16
X-Sex-Linked Pedigree

• Shows gender bias with males exhibiting the trait
  more often than females

17
(No Transcript)
18
Autosomal Dominant Pedigree

• Autosomal dominant traits do not skip a
  generation
• Autosomal dominant traits do not show gender bias

19
Autosomal Recessive Pedigree

• Autosomal recessive traits skip a generation
• Autosomal recessive traits do not show gender bias

20
Fill in Genotypes
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
Gene Location

• Linked Linkage Groups genes located so close
  together on a chromosome that the traits always
  seem to appear together
• Ex. Red hair and freckles
• Ex. Colorblindness and Hemophilia

X X
25
Gene Interactions

1. Polygenetic trait many genes influence a single
   trait (ex. Height, intelligence)
2. Pleiotropic effect one gene having many effects
   (ex. Gene to make testosterone)

26
Pleiotropy
?

• Expression of a single gene which has multiple
  phenotypic effects
• Marfan Syndrome abnormal gene that makes
  fibrillin (important in connective tissues)

27
Non-Mendelian Genetics

• Incomplete Dominance blended inheritance
• Neither form of the gene is able to mask the
  other
• Ex. Snap dragon petal color
• R1R1 RED
• R1R2 PINK
• R2R2 - WHITE

28
Try these

• In a plant species, if the B1 allele (blue
  flowers) and the B2 allele (white flowers) are
  incompletely dominant (B1 B2 is light blue), what
  offspring ratio is expected in a cross between a
  blue-flowered plant and a white-flowered plant?

29

• What would be the phenotypic ratio of the flowers
  produced by a cross between two light blue
  flowers?

30

• 2. Oompas can have red (H1H1), blue (H2H2), or
  purple hair (H1H2). The allele that controls
  this is incompletely dominant. A purple haired
  Oompa marries a blue haired Oompa. What will
  their children be like? Give phenotypic and
  genotypic ratios.

31
Codominance

• No dominance and both alleles are completely
  expressed
• Ex. Cat color
• C1C1 Tan
• C1C2 Tabby (black and tan spotted)
• C2C2 - Black

32
Try These

• Cattle can be red (RR all red hairs), white (WW
  all white hairs), or roan (RW red white
  hairs together.
• Predict the phenotypic ratios of offspring when a
  homozygous white cow is crossed with a roan bull.
  

33

• What should the genotypes phenotypes for parent
  cattle be if a farmer wanted only cattle with
  roan fur?

34

• A cross between a black cat a tan cat produces
  a tabby pattern (black tan fur together).
• What pattern of inheritance does this illustrate?
  
• What percent of kittens would have tan fur if a
  tabby cat is crossed with a black cat?

35
Multiple Alleles

• More than 2 alleles for one trait
• Ex. Eye color, hair color, blood type, guinea pig
  fur color
• ABO blood groups
• Each individual is A, B, AB, or O phenotype
• Phenotype controlled by marker on RBC
• IA and IB alleles are dominant to the i allele
• IA and IB alleles are codominant to each other

36
Blood Types

• Blood Type
• A
• B
• AB
• O

• Genotype
• IAIA, IAi
• IBIB, IBi
• IAIB
• ii

37
(No Transcript)
38
(No Transcript)
39
Try These

1. If a male is homozygous for blood type B and a
   female is heterozygous for blood type A, what are
   the possible blood types in the offspring?

40

1. Is it possible for a child with Type O blood to
   be born to a mother who is type AB? Why or why
   not?

41

1. A child is type AB. His biological mother is
   also type AB. What are the possible phenotypes
   of his biological father?

42
V. Genetic Conditions

• Genetic Abnormality rare condition with little
  or no ill effects
• - Ex. Six fingers, albino, colorblindness

43
2. Genetic Disorders

• Inherited condition that results in a medical
  problem
• - Ex. Huntingtons Disease, Sickle Cell Anemia,
  Hemophilia, Muscular Dystrophy

44
3. Genetic Disease

• A genetic condition that makes the individual
  susceptible to infection (bacterial or viral)
• - Ex. Cystic fibrosis, Down syndrome, SCID
  (severe combined immunodeficiency disease
  bubble boy)

45
VI. Mutations

• Definition any change in the DNA
• Possible outcomes good, bad, or no effect
• Location
• Somatic Cell (body cell) can lead to cancer
• Sex Cell reproductive organ affecting gametes

46
Observed vs. Expected Ratios

• Observed Ratio what you actually get from two
  organisms having offspring ex. having all
  girls
• Expected Ratio based on your Punnett square
  results what you would expect to get ex. half
  girls and half boys
• Another Example using dice

47
Human Genetics Test Topics

• Sex-linked Traits
• Incomplete Dominance/ Codominance
• Multiple Alleles (blood typing problems)
• Genetic Conditions
• Sex Chromosomes vs. Autosomes
• Pedigrees/Karyotypes
• Observed vs. Expected Ratios
• LOTS OF GENETICS PROBLEMS SHOW WORK!!!

48
Human Genetics Test Review Questions

• My daughter is type A, my grandson is type B.
  What are the blood type(s) that the father would
  have to be in order for my grandson to be type B?
  

49

• Red-green color blindness is X-linked in humans.
• If a male is red-green color blind, and both
  parents have normal color vision, which of the
  male's grandparents is most likely to be
  red-green color blind?
• A. maternal grandmother B. maternal
  grandfather C. paternal grandmother D.
  paternal grandfather E. either grandfather is
  equally likely

50

• Suppose a child is of blood type A and the mother
  is of type 0. What type or types may the father
  belong to?

51

• Suppose a father and mother claim they have been
  given the wrong baby at the hospital. Both
  parents are blood type A. The baby they have been
  given is blood type O. What evidence bearing on
  this case does this fact have?

52

• Hemophilia is a sex-linked recessive trait. Cross
  a hemophiliac female with a normal male. Of all
  their offspring, what is the probability they
  will produce a hemophiliac daughter? (H normal
  blood, h hemophilia)

53

• A man with Type A blood marries a woman with Type
  B blood. They have a type O child. What is the
  probability of their 15th child having type O
  blood?

54

• A man whose father is type B and whose mother is
  type A, has a blood type of A. He marries a type
  A woman, whose parents had the same blood types
  as his parents. What are the genotypes of the
  man and the woman and what is the probability
  that their first child will be blood type A?

55

• Coat color in cats is a codominant trait. Cats
  can be black, yellow or calico. A calico cat has
  black and yellow splotches. In order to be
  calico. the cat must have an allele for the black
  color and an allele for the yellow color. Show a
  cross between a calico cat and a yellow cat.
  What are the possible genotypes and phenotypes of
  the offspring?

56

• A mother and father with normal color vision
  produce six male children, two of whom exhibit
  red-green colorblindness. Their five female
  children exhibit normal color vision. Ignoring
  the fact that these parents ought to seek some
  family planning advice, explain the inheritance
  of red-green colorblindness in their male
  children.

57
A nurse at a hospital removed the wrist tags of
three babies in the maternity ward. She needs to
figure out which baby belongs to which parents,
so she checks their blood types. Using the chart
below, match the baby to its correct parents.
Show the crosses to prove your choices
Parents Blood Types Baby Blood type
Mr. Hartzel O    
Mrs. Hartzel A Jennifer O
Mr. Simon AB Rebecca A
Mrs. Simon AB Holly B
Mr. Peach O
Mrs. Peach O
58
(No Transcript)