Question

solve this question​

Answer 1

Answer:

(a) Rolling and non rolling of tongue is result of genetic inheritance  with,

    Dominant trait- Roller tongue 'R'

    Recessive trait- Non roller tongue 'r'

The trait shown here is of non rolling hence a 'recessive trait'.

Identification of dominant or recessive trait:

   i) Simple rule and easy identification

• Trait that occurs in parents and is also seen in first generation and also continues in the second generation are dominant trait.

• If a specific trait does not occur in parents but occur in the next generation, and may or may not be present on the further generation Then this is a possible case of a recessive trait

  ii) Complicated method

Try hit and trial method and find out the genotype of all the possible individual and then decide which trait is it.

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(b)Predicting the possible genotype of the individuals.

Since there is a inheritence due to recessive trait, parents are possibly both heterogenous individuals

Let the dominant trait be 'R'and recessive trait 'r'

So genotype of parents both are 'Rr'

Now of their offsprings: Rr X Rr

When during crossing the offsprings genotype: RR, Rr,rr,Rr respectively

• Hence due to 'rr' genotype  in the 3rd offspring the offspring have a non roller tongue.

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Hope Its clear!!