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.

1 comment:

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