Name:_______________________________Date:__________Period:_____________
NonMendelian Genetics Review – Smith 2015
Inc/ Co Dominant, Sex Determination, Sex Linkage, Nondisjunction, Pedigree, Karyotyping
Some Punnett Squares are not completed due to the complexity of typing them. Sorry for any inconvenience.
Write your answer in the numbered blanks. Word bank is for questions 1-14
Multiple Alleles
Sex-linked (X)
Somatic
Beard
Down’s Syndrome
Autosomes
23
Colorblindness
Hemophilia
Mutation
Blood
23
Drosophila
(Trisomy 21)
1. somatic They are considered the “body cells”; any cells excluding sex
cells.
2.46 or 23 Human cells have _____ or _____pair of chromosomes.
3.23
Human gametes have _______ chromosomes.
4.autosomes They are considered the “body chromosomes”; any pair of
chromosomes excluding sex chromosomes.
5.sex-linked (X) A recessive trait carried on the X type of chromosome.
6.Drosophilia Scientific name of the fruit fly; see practice problems
7.mutation is a sudden genetic change.
8.non-disjunction is the abnormal segregation of chromosomes.
9.Down’s Syndrome (Trisomy 21) results in 3 X’s in 21st pair
10.multiple alleles having many alleles for one trait
11.Blood Type give an example for #10.
12.Colorblindness and Hemophilia 2 sex-linked diseases
13. Sex-Limited a characteristic where genes are present in both sexes but
traits show up only in one sex.
14.beard, breast give 2 examples for #13.
46
Non-disjunction
Sex limited
Breasts
Word bank for questions 15-25
Mother
i (O)
IA
100%
Hemophilia
Karyotype
Y
50%
IAIB
IB
15._________ 100%_________ What % of offspring get a X chromosome?
16.____ Hemophilia ________
A sex-linked disease when blood does not clot properly.
17.___ IA ___, ___ IB _____
Name 2 dominant genes in blood.
18.______ IAIB ________
Name the blood type that shows codominance.
19._______ i (O) _________ Name the recessive blood allele.
20._____ Mother ______ A male inherits a sex-linked trait from which parent?
21.________ 50%_________ What % offspring get a Y chromosome from their father?
22._____________________ Symbol for male
23._________________ Symbol for female
24. _________ Y _________ The male sex chromosome is ____.
25.____ Karyotype ____ - an array of chromosomes found in an individual’s cells at
metaphase of mitosis and arranged in homologous pairs and in
order of diminishing size.
-------------------------------------------------------------------------------------------------------(no word bank)
26. Name the 4 blood types and their respective genotypes.
Phenotype/Genotype
A
– AA, AO
B
– BB, BO
O
- OO
AB
- AB
Word Bank for questions 27-42.
Hormones
Polygenic
Estrogen
Banding pattern
Smallest
Pedigree
Trisomy
Non-disjunction
gender
carrier
Monosomy
environment
roman
largest
testosterone
chromosomes
arabic
size
27. polygenic
traits develop from the interaction of multiple pairs of genes.
Ex. skin color, eye color, height. Human skin color is thought to
be controlled by 12 genes!
28. The environment influences many traits. Factors such as sunlight, temperature,
and water can affect an organism’s phenotype. Ex. Siamese catcooler parts of the cat’s body , such as the ears, nose, feet and
tail are darker. Heart disease can be inherited, but diet and
exercise also strongly influence the disease.
Sex-limited/Sex-influenced – Genes are present in both male and females, but show up only in
one sex due to the presence of 29. hormones. The examples of this are a man’s beard,
development of breasts and the plumage in birds. These occur because of the hormone
30.testosterone in males and 31. estrogen in females.
Explain why the trait for hemophilia and colorblindness is rare in females?
The traits for colorblindness and hemophilia are “X-linked” traits. The traits are only carried
on the X chromosome. Males have only one X chromosome so
their options are to either have the trait or not. Females have 2
X chromosomes so females have a second chance to mask the
recessive trait.
Nondisjunction
During cell division, the chromosomes separate, with one
of each of the sister chromatids going to opposite poles
of the cell. Therefore, each new cell has the correct
number of chromosomes.
If sister chromatids fail to separate properly in cell
division 32. Non-disjunction occurs
If nondisjunction occurs during meiosis I or meiosis II,
the resulting gametes will not have the correct number
of33. chromosomes.
When one of these gametes fertilizes another gamete,
the resulting offspring will not have the correct number
of chromosomes
O Notice that nondisjunction can result in extra copies of a certain chromosome or only one
copy of a particular chromosome in the offspring.
O 34.Trisomy set of three chromosomes of one kind
O 35.Monosomy only one of a particular type of chromosome
Complete the punnett square by showing an example of non-disjunction in sex cells.
This is one way genetic disorders can be passed to the offspring
Nondisjunction in the female
Nondisjunction in the male
X Y x X X
In the female, the X’s could stay together leaving
some eggs with 2 X’s and some eggs with no sex
chromosome (O)
X Y x X X
In the male, the X’s and Y’s could stay together
leaving some sperm with XY and some sperm with
no sex chromosome (O)
XX
O
X
XXX
XO
XY
XXY
XXY
Y
XXY
OY
O
XO
XO
X
X
XO – Turner’s Syndrome (female), XXY – Klienfelter’s Syndrome (male), XXX – Super Female, OY – will not survive
--------------------------------------------------------------------------------------------------------36. Scientists use a diagram called a pedigree to trace inheritance of trait through several
generations.
37. An individual who has the gene but not the disease is called a carrier.
Draw Symbols used in a pedigree. Refer to your pedigree worksheet/notes.
_____- Normal female
_____- Normal male
_____- Female who expresses trait
_____- Male who expresses trait
_____- Female who is a carrier
_____- Male who is a carrier
_____- Marriage
_____- Siblings
38. Roman numbers are used to represent generations
39. Arabic numbers are used to represent individuals in a certain generation
I
II
III
How many generations are represented in the pedigree?3
How many children do II5 and II6 have?3
What is the relationship between III5 and I2? Grandson and grandmother
What is a Karyotype? (refer to notes, computer packet or cinch packet)
A micrograph of whole chromosomes that allow scientists to view all 23 pair in a human cell
40. Scientists use size, banding pattern and centromere position as a guide in making a
karyotype.
41. In a karyotype, chromosome are arranged and numbered from largest to smallest.
42. In a karyotype, the last pair of chromosomes determine gender (male or female.)
Is this karyotype normal or abnormal?abnormal because there
are 3 chromosome #21 and there should only be 2 of each
chromosome.
Why?This is Trisomy 21 or Down Syndrome
Word Bank for questions 43-48
Identical
Fraternal
Multiple Alleles
Klinefelter’s
Blood
Turners
43.Name the form of inheritance that is determined by more than two alleles. Multiple alleles
44.An example of such a trait is Blood Type.
45. Fraternal twins-these individuals arise from and develop from separate eggs fertilized by
separate sperm. Can they be different genders?Yes
46. Identical twins- these individuals started as a single egg fertilized by one sperm.
47.Klinefelter’s – XXY syndrome- male with 47 chromosomes. An extra “X” is present
48.Turner’s – XO syndrome- female with 45 chromosomes Only one “X” chromosome is present
49.Who determines the sex (gender) of a child? MALE
Show your work
Sex-linked Problems
50.A father with hemophilia and a mother who is normal but is a carrier for hemophilia
have children.
The correct gene(s) for the father would be:Xh Y
The correct genes for the mother would be: XHXh
Out of four children, the expected number of girls with hemophilia would be: 1 out of 4 chance
Out of the four children, the expected number of boys with hemophilia would be: 1 of 4 chance
Out of the four children, how many boys and girls would be normal? 2 of 4 chance normal
51.A color-blind male and a normal non-carrier female have a child. Complete a punnett
square. Write all results.
Multiple allele problem:
52. The possible blood types of the offspring resulting when a heterozygous type A person
is crossed with type 0. Complete a punnett square and write all results.
53. What is meant by incomplete dominance? Neither trait is dominant, incomplete dominance is
seen as a “blend” or mixture and creates a third genotype that looks nothing like the parents
54. Red (r) is incompletely dominant to white (w) producing pink (rw) offspring. Show a cross
between a red snapdragon flower and a pink snapdragon flower. Show all steps.
55. Define Codominance-Both traits are dominant, codominance is shown as spots or stripes
typically, both dominant traits will be visible in the codominant organism
56. In chicken, black feather color(B) is codominant to white feather color (W). The
heterozygous individual is a combination of black and white feathers that results in a checkered
pattern (BW) called erminette. Cross a checkered chicken with a checkered chicken. Show all
steps.
What percentage of the offspring will be Black? 1 of 4 or 25% White? 1 of 4 or 25%