HEREDITY
MONOHYBRID CROSS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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25%
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50%
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75%
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100%
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Detailed explanation-1: -3 Punnett Square. Since Gilbert can hear, his two possible genotypes are homozygous dominant ( DD ) and heterozygous ( Dd ). If after breeding there are any deaf puppies, his genotype is heterozygous ( Dd ). If there are none, his genotype is therefore homozygous dominant ( DD ).
Detailed explanation-2: -Hereditary deafness can be either cochleosaccular or neuroepithelial in origin. Cochleosaccular is the most common cause of deafness and is associated with coat color patterns. It is usually seen in dogs with the piebald color genes or merle color gene.
Detailed explanation-3: -In dogs, there is a hereditary deafness caused by a recessive gene, “d”. A kennel owner has a male dog that she wanted to use for breeding purposes if possible. The dog can hear, so the owner knows his genotype is either DD or Dd.
Detailed explanation-4: -If deafness is carried as a theoretical simple autosomal recessive gene (d), the breeding of two hearing carriers (Dd) (Table 1) will result, on average, in 25% affected dogs (dd), 50% hearing carriers (Dd), and 25% free of the defect (DD).