PEDIGREE ANALYSIS: PRACTICE PROBLEMS

Q1. Identify the inheritance pattern in the following picture.


The above pedigree is Autosomal recessive. 

  • Recessive because there is skipping of generation.
  • Autosomal recessive because, it does not fulfill X-linked recessive condition.

For X-linked recessive, following conditions must be fulfilled:
  1. More boys affected than girls
  2. Female does not affect female
  3. Affected mom has to have affected sons as well as dad

Q2. Identify the mode of inheritance.



The above pedigree is X-linked dominant because of the following reasons:

1. Dominant because there is no skipping of generation.
2. X-linked dominant condition must follow DDD rule (the first D represents dominant condition; the second D represents affected D; the third D represents daughters). It means, in a dominant condition, if dad is affected, all his daughters will be affected too.
3. The above pedigree follows DDD rule.




Q3. Identify the mode of inheritance.

Autosomal dominant

No DDD rule followed in the above pedigree

Q4. Identify the pattern of inheritance.


Autosomal recessive

No X-linked recessive condition followed.

Q5. Identify the pattern of inheritance.

X-linked recessive

Followed X-linked recessive condition.
It is recessive because two unaffected parents produced affected offspring -- a characteristic of recessive trait. 


Q6. Find the pattern of inheritance in the following pedigree and write the genotype of III 7


 

16 comments:

  1. quite easy questions....... please upload some more !

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  2. better to student....please upload more

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  4. These were basic...hoping for further tasking questions...

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  5. Replies
    1. The answer for question no.6 is Autosomal dominant.
      Autosomal because male child and female child got trait from there parents
      And dominant because each generation has a trai..

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    2. Autosomal dominant

      Not recessive because
      1. Affected son (7) has unaffected mother (3)
      2. Affected mother (4) has unaffected daughter (8)

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  8. Pooja, the answer to question 6 is Autosomal dominant. It is dominant because there is,no skipping of generation and it is Autosomal dominant because it doesn't follow DDD rule. The genotype of III 7 is As.

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  9. very helpful and makes us understand easily

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  10. Plz add some more Qs...I would lyk 2 know more

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  11. What's the answer of sixth one
    I think its autosomal dominant
    Plz reply

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  12. I think its an autosomal dominant trait

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