1. Mexican hairless dogs are heterozygous (Hh), carrying a single copy of a rece

Question

1. Mexican hairless dogs are heterozygous (Hh), carrying a single copy of a recessive lethal allele (hh homozygotes are dead, and HH individuals have hair). In a given population, 60% of the individuals are HH and 40% are Hh. What are the allele frequencies in this population? a.0.50 H and 0.50 h b. 0.20 H and 0.80 h c. 0.80 H and 0.20 h d. 0.77 H and 0.23 h e. 0.60 H and 0.40 h Correct Answer C 2. Mexican hairless dogs are heterozygous (Hh), carrying a single copy of a recessive lethal allele (hh homozygotes are dead, and HH individuals have hair). In a given population, 60% of the individuals are HH and 40% are Hh. What are the allele frequencies in this population? Please explain part 2

Explanation / Answer

Ans.2) The phenotype of hairlessness is a due to their heterozygous genotype. Having hair is a result of being a homozygous recessive genotype. The homozygous dominant genotype is a lethal phenotype, resulting in death.

Here, suppose allele for hairlessness = "H" and allele for hair "h"
Hairless dog has the genotype "Hh" and hairy dog has the genotype "hh"
When these individuals with theses two allels are crossed, 50% hairy and 50% hairless progeny produced and these are
H h, h Hh hh, h Hh hh
Now when the cross is made between two hairless dogs "Hh" x "Hh" and progeny are
H h, H HH Hh, h Hh hh

In this population, the offsprings with "HH" genotype will die. But the remaining 3/4 offspring, 1/3 are "hh" and hairy, whereas the rest (2/3) are "Hh" and hairless.

Hence, according to given information 60% of the individuals are HH and 40% are Hh and Hardy-Wienberg Equation= p+q= 1

Hence, allelic frequency of HH (0.6) and Hh (0.4)

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