CBSE Class 10 Answered
Two human beings who can both roll their tongues produced 11 children. 3 of these children could not roll their tongues and 8 children could roll their tongues. (a) Which trait (rolling or not rolling) is controlled by the recessive allele? (b) State all possible genotypes of the F1 generation of the cross. Show the inheritance of the tongue rolling in humans in the given example using a suitable cross. What percentage of offspring will show the same genotype as the parents? OR (c) If one of the parents could not roll their tongue, with the help of a cross, calculate the ratio of tongue- rollers to non-tongue-rollers in the off springs.
Asked by Venkata Raman | 06 Feb, 2023, 06:59: PM
Question states that both the parents are tongue-rollers but not all the offspring are tongue-rollers. So, we can conclude that parents are heterozygous for the character.
So the genotype for parents will be Tt (heterozygous for tongue-rolling) where T is dominant and t is a recessive character.

(a) Tongue rolling is dominant (TT/Tt) while non-rolling is recessive (tt).
(b) Possible genotypes of the F1 generation of the cross - TT, Tt, tt
So, 75% of the offpsring are tongue rollers while 25% are non-rollers.
50% of the offpspring will show the same genotype (Tt) as that of the parents.
(c)

(c) Ratio of tongue- rollers to non-tongue-rollers in the offspring = 1:1
50% are tongue rollers while 50% are non-rollers.
Answered by Sheetal Kolte | 07 Feb, 2023, 01:08: PM
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