Question

question 4
a male dog that is heterozygous for long ears (li) and heterozygous for a pointed nose (nn) is mated with a female dog that is also heterozygous for both traits.
what is the phenotypic ratio for this cross?____

Explanation:

Step1: Determine the dominant and recessive traits

Assume \(L\) (long ears) is dominant over \(l\) (short ears) and \(N\) (pointed nose) is dominant over \(n\) (non - pointed nose).

Step2: Analyze the genotypes in the Punnett square

• \(LLNN\): long ears, pointed nose
• \(LLNn\): long ears, pointed nose
• \(LlNN\): long ears, pointed nose
• \(LlNn\): long ears, pointed nose
• \(LLnn\): long ears, non - pointed nose
• \(Llnn\): long ears, non - pointed nose
• \(llNN\): short ears, pointed nose
• \(llNn\): short ears, pointed nose
• \(llnn\): short ears, non - pointed nose

Count the number of each phenotype:

• Long ears, pointed nose (\(L - N-\)): \(9\) ( \(LLNN+LLNn+LlNN+LlNn\) )
• Long ears, non - pointed nose (\(L - nn\)): \(3\) ( \(LLnn+Llnn\) )
• Short ears, pointed nose (\(llN-\)): \(3\) ( \(llNN+llNn\) )
• Short ears, non - pointed nose (\(llnn\)): \(1\)

Answer:

\(9:3:3:1\)