Pedigree problems (NEET)

Explains how to solve pedigree problems asked in previous NEET exams

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 Autosomal Recessive X-linked dominant Autosomal dominant X-linked recessive

3. NEET 2015 In the following human pedigree, the filled symbols represent the affected individuals. Identify the type of given pedigree Autosomal Recessive X-linked dominant Autosomal dominant 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 Autosomal Recessive X-linked dominant Autosomal dominant 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 Autosomal Recessive X-linked dominant Autosomal dominant 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 Autosomal Recessive X-linked dominant Autosomal dominant 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 Autosomal Recessive X-linked dominant Autosomal dominant 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 Autosomal Recessive X-linked dominant Autosomal dominant 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 The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness 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 The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness 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 The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness The male parent is homozygous dominant   X d X d X D X D X d Affected daughter X D X d Affected daughter Y X d Y Normal Son X d Y 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.   X D X D X d X D X d Carrier daughter X D X d Carrier daughter Y X D Y Normal Son X D Y Normal Son Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the characterIf The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness 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   X D X d X d X D X d Carrier daughter X d X d Affected daughter Y X D Y Normal Son X d Y Affected Son Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the characterIf The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness 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   X D X d X d X D X d Carrier daughter X d X d Affected daughter Y X D Y Normal Son X d Y Affected Son Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the characterIf The female parent is heterozygous The parents could not have had a normal daughter for this character The trait under study could not be colour blindness 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 Bo th sexes are affected So Aut osomal

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 Bo th sexes are affected So Aut osomal 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 Bo th sexes are affected So Aut osomal 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 Bo th sexes are affected So Aut osomal 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 Bo th sexes are affected So Aut osomal 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