Asksia AI LOGO

Sia

Question
Biology
Posted about 2 months ago
If all the offspring from a test cross are of the dominant phenotype, is the parent with the dominant phenotype homozygous or heterozygous? Briefly explain how you know.
Sign in to unlock the answer
Answer from Sia
Posted about 2 months ago
Answer
The parent with the dominant phenotype is homozygous.
Solution
a
Test cross: A test cross involves crossing an individual with a dominant phenotype (but unknown genotype) with an individual that is homozygous recessive for the trait
b
Offspring phenotypes: If all offspring display the dominant phenotype, it indicates that the parent with the dominant phenotype must be homozygous dominant (AA)
c
Genotype determination: If the parent were heterozygous (Aa), we would expect a 1:1 ratio of dominant to recessive phenotypes in the offspring
Key Concept
Homozygous dominant genotype results in all offspring showing the dominant phenotype in a test cross.
Explanation
In a test cross, if the parent with the dominant phenotype is homozygous (AA), all offspring will inherit at least one dominant allele, resulting in the dominant phenotype. If the parent were heterozygous (Aa), some offspring would inherit the recessive allele from both parents, showing the recessive phenotype.

Not the question you are looking for? Ask here!

Enter question by text

Enter question by image

Upgrade to Asksia Pro

Join a AskSia's Pro Plan, and get 24/7 AI tutoring for your reviews, assignments, quizzes and exam preps.

Unlimited chat query usages
Strong algorithms that better know you
Early access to new release features
Study Other Question