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In humans, dimples are dominant to no dimples and long eyelashes are dominant to short. A man with no dimples and short eyelashes mates with a woman who is heterozygous for both traits. Determine the phenotypic ratio of the offspring. Also determine what percentage of their offspring will have the same genotype as their mother.

Answer :

The phenotype ratio of the offspring is 1:1:1:1

25% progeny will have the genotype similar to their mother. DdLl

Explanation:

Dimples are dominant  = D  long eyelashes are dominant = L

no dimples are recessive = d  short eyelashes are recessive = l

The genotype of the man with no dimples and short eyelashes

ddll

The genotype of the woman who is heterozygous for both the traits

DdLl

From the Punnet square:

         dl     dl    dl    dl

Dl   Ddll   Ddll   Ddll Ddll

DL DdLl  DdLl   DdLl DdLl

dL ddLl  ddLl    ddLl  ddLl

dl  ddll   ddll    ddll    ddll

The genotype ratio is= 1:1:1:1

Phenotype ratio= 1:1:1:1

 ( from the results 4 progenies of each genotype combination and phenotype traits as ( Ddll  dimple-short eyelashes, DdLl Dimples and long eyelashes, ddLl no dimples- long eyelashes, ddll no dimples short eyelashes.)

The mother is heterozygous for both the characters so 25% of the progeny will have the same genotype as their mother.

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