BIOLOGY
GENETICS
6. If a couple’s first child is a boy, what is the
probability that their next child will be a girl? Why?
Topic 9: Chromosome Theory
b) What is the meaning of linkage?
Answer: 50%
2. Two individuals have genes like in diagrams given
below. A and B genes are linked but D gene
independent from A and B.
If we crossed these two individuals, what would be
seen in their offspring?
7. Four genes (A, B, C, and D) are on the same
chromosome. The crossing-over frequencies below are
obtained. What is the correct sequence of genes?
A- B 19%
B-C 14%
A-C 5%
B-D 2%
A-D 21%
C-D 16%
Answer: ACBD
Topic 11: Sex-Linked Inheritance in Humans
A
a
B
b
D
d
a
a
b
b
d
d
1. If a normal-sighted but carrier woman marries with a
colorblind man, what is the probability of colorblind
girl that they will have?
2. Which important genetic disease’s genes are carried
by human X chromosome?
1st individual
3. Which genetic disease’s genes are carried by human
Y chromosome?
2nd individual
4. What is the most important property of Y linked
inheritance?
5. What is the Hemophilia?
3. If two genes are linked, _____.
A) they are on different chromosomes
B) they assort independently
C) they code for the same protein
D) they are on the same chromosome
E) they are on sex chromosomes
6. A Hemophilia carrier woman married a man that has
normal blood clotting property. What is the probability
of Hemophilia children that they will have in their
offspring?
7. What is the probability that a male will inherit an Xlinked recessive allele from his father?
Topic 10: Chromosome Maps
1. Give an example to phenotypic sex determination.
2. Which chromosome/s determine/s the sex (gender)
of human?
3. Write the sex of humans having following
genotypes.
Answer: 0%
8. A woman is a carrier for red-green colorblindness, a
sex-linked trait. Her husband is normal (not colorblind)
for this trait. What is the chance that their newborn
daughter will be red-green color-blind?
Answer: 0%
XY:
Topic 12: Non-disjunction
XX:
1. What is the meaning of Non-disjunction?
XXX:
2. Write the name of the following Nondisjunction
diseases.
XXXX:
44+XXY:
XXYX:
44+XXX:
4. Which parent (male and female) determines the sex
of child in Human? Why?
5. Sex determination of some social insects such as
honeybee, wasp, and ants is regulated by chromosome
numbers.
(Haploid: n Diploid: 2n)
Write chromosome numbers and sex of the
following organisms.
Queen:
Soldier:
Worker:
Drones:
Date: ____/_____________/ 2011
44+XO:
45+XY:
45+XX:
3. One person has triple 21st chromosomes in its
karyotype. What kinds of disorders are found in its
body? Explain.
4. What is the problem in the super female disease?
5. Explain the non-disjunction process with figures.
6. What is the turner syndrome?
7. Which one of the following is the only known
viable human Monosomy?
A) XYY
B) XO
C) YO
D) XY
E) XXY
Signature: _____________________
BIOLOGY
GENETICS
Topic 15: Human Karyotype and Idiogram:
Topic 16: Pedigree
1. Explain the following terms.
Haploid Chromosomes:
Diploid Chromosomes:
Homologous Chromosomes:
4A.
1
2
2. Answers to questions according to following
Human karyotype picture.
3
4
5
The pedigree given above shows an autosomal
recessive disease in a family. 2nd and 4th individuals
have this disease.
What can be said about 1st, 3rd and 5th individuals?
Why? Explain.
1st:
3rd:
2A. How many chromosomes are found in a Human
cell?
_______
2B. How many homologous chromosomes are found in
the picture?
_______
2C. What are the properties of X and Y chromosomes?
_______ ________________________
2D. What is the gender of this person?
3. This diagram shows a family tree (pedigree) of
colorblindness.
5th:
4B. The pedigree given below shows a sex –linked
recessive disease. In this family mother has this
disease but father does not.
In the pedigree, 1st and 2nd individuals were given
correctly in figure but were not the others.
What can be said about 3rd, 4th and 5th individuals?
Why? Explain.
Normal
male
1
1
2
2
Normal
female
Colorblind
male
3
4
5
3
Colorblind
female
3rd:
Which of the following cannot be said about this
family? (Colorblindness is a sex linked recessive disease)
A) 1st person is homozygote dominant
B) 2nd person has only one gene about colored vision
C) 3rd person can be homozygote and heterozygote.
D) 4th person has colorblind diseases
E) 5th person doesn’t have any colorblind gene
Date: ____/_____________/ 2011
4th:
5th:
Signature: _____________________
4
5