The document describes a pedigree analysis to determine the mode of inheritance shown. It analyzes a pedigree where normal parents produce affected offspring in generations II and III. This indicates recessive inheritance. As it skips generations and not all offspring are affected, it also points to recessive inheritance. Autosomal recessive and X-linked recessive are considered, but X-linked recessive is ruled out. Therefore, the mode of inheritance is determined to be autosomal recessive.

1. PEDIGREE ANALYSIS
NEET PROBLEMS SOLVED
Dr. Valli Syam

2. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive

3. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive

4. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Skips generation
– Few II & many III generation individuals not
affected
So Recessive

5. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Skips generation
– Few II & many III generation individuals not
affected
So Recessive
Option B and C ruled out

6. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Skips generation
– Few II & many III generation individuals not
affected
So Recessive
Option B and C ruled out
If X – linked recessive,
II generation affected daughter should give rise to
affected son in III generation - But here son is normal
X – Linked inheritance is ruled out
Option D ruled out

7. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Skips generation
– Few II & many III generation individuals not
affected
So Recessive
Option B and C ruled out
If X – linked recessive,
II generation affected daughter should give rise to
affected son in III generation - But here son is normal
X – Linked inheritance is ruled out
Option D ruled out
Therefore, Option A is correct
It is an Autosomal Recessive pedigree

8. NEET 2015
In the following human pedigree, the filled symbols
represent the affected individuals. Identify the type of
given pedigree
a. Autosomal Recessive
b. X-linked dominant
c. Autosomal dominant
d. X-linked recessive
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Skips generation
– Few II & many III generation individuals not
affected
So Recessive
Option B and C ruled out
If X – linked recessive,
II generation affected daughter should give rise to
affected son in III generation - But here son is normal
X – Linked inheritance is ruled out
Option D ruled out
Therefore, Option A is correct
It is an Autosomal Recessive pedigree

9. Which one of the following symbols and its
representation, used in human pedigree analysis is
correct?
NEET 2010
Mating between relative
Unaffected male
Unaffected female
Male affected

10. Which one of the following symbols and its
representation, used in human pedigree analysis is
correct?
NEET 2010
Mating between relative
Unaffected male
Unaffected female
Male affected
Square denotes male – Wrong Option
Round denotes female – Wrong Option
Diamond denotes Sex not known – Wrong Option
Option 1 is correct

11. Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant
NEET 2010

12. a a
A Aa Aa
A Aa Aa
If the disease is Autosomal dominant and father is homozygous
dominant all the offspring will be affected – But one normal
son is there – So Option D is ruled out
Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant
NEET 2010

13. Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant
Xd Xd
XD XDXd
Affected daughter
XDXd
Affected daughter
Y XdY
Normal Son
XdY
Normal Son
If the disease is X – linked dominant – Sons will not be affected
as mother is homozygous recessive (Normal) – But one Son is
affected – So the disease is not X – linked dominant
NEET 2010
Affected father giving rise to more affected daughters indicates
that the disease may be X – linked

14. XD XD
Xd XDXd
Carrier daughter
XDXd
Carrier daughter
Y XDY
Normal Son
XDY
Normal Son
Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant
If the disease is X – linked recessive – Mother is homozygous –
all Sons will be Normal – But one son is affected – So mother is
not homozygous (she is heterozygous - carrier) – More towards
Option A
NEET 2010

15. If the disease is X – linked recessive – Both normal and affected
Sons and also affected daughters and Normal (Carrier)
daughters are possible [Option B ruled out] only if mother is
heterozygous (Carrier) – Option A is correct
XD Xd
Xd XDXd
Carrier daughter
XdXd
Affected daughter
Y XDY
Normal Son
XdY
Affected Son
Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant Colour blindness is a X – linked recessive disease – so Option C
is ruled out
NEET 2010

16. If the disease is X – linked recessive – Both normal and affected
Sons and also affected daughters and Normal (Carrier)
daughters are possible [Option B ruled out] only if mother is
heterozygous (Carrier) – Option A is correct
XD Xd
Xd XDXd
Carrier daughter
XdXd
Affected daughter
Y XDY
Normal Son
XdY
Affected Son
Study the pedigree chart of a certain family
given below and select the correct
conclusion which can be drawn for the
characterIf
a. The female parent is heterozygous
b. The parents could not have had a normal
daughter for this character
c. The trait under study could not be colour
blindness
d. The male parent is homozygous
dominant Colour blindness is a X – linked recessive disease – so Option C
is ruled out
NEET 2010

17. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009

18. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive

19. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Both sexes are affected
So Autosomal

20. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Both sexes are affected
So Autosomal
Pedigree chart is an example for Autosomal recessive.
Therefore, Pedigree chart can not be said as an
impossible one – Option B is wrong

21. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Both sexes are affected
So Autosomal
Pedigree chart is an example for Autosomal recessive.
Therefore, Pedigree chart can not be said as an
impossible one – Option B is wrong
The father is normal so daughter will not be affected if
the disease is a recessive disease like haemophilia –
Option C is wrong

22. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Both sexes are affected
So Autosomal
Pedigree chart is an example for Autosomal recessive.
Therefore, Pedigree chart can not be said as an
impossible one – Option B is wrong
The father is normal so daughter will not be affected if
the disease is a recessive disease like haemophilia –
Option C is wrong
Phenylketonuria is not a Sex-linked disorder – Option D
is wrong
Phenylketonuria is an autosomal recessive trait
– Option A is correct

23. Study the pedigree chart given below. What does it
show?
a. Inheritance of a condition like phenylketonuria as an
autosomal recessive trait
b. The pedigree chart is wrong as it is not possible
c. Inheritance of a recessive sex-linked disease like
haemophilia
d. Inheritance of a sex-linked inborn error of metabolism
like phenylketonuria NEET 2009
Normal parents giving rise to diseased offspring (II and
III generation)
So Recessive
Both sexes are affected
So Autosomal
Pedigree chart is an example for Autosomal recessive.
Therefore, Pedigree chart can not be said as an
impossible one – Option B is wrong
The father is normal so daughter will not be affected if
the disease is a recessive disease like haemophilia –
Option C is wrong
Phenylketonuria is not a Sex-linked disorder – Option D
is wrong
Phenylketonuria is an autosomal recessive trait
– Option A is correct