Textbook Problem

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A testcross is a way to determine ________.

1. a. phenotype
2. b. genotype
3. c. dominance

Summary Introduction

Concept Introduction: Testcross and backcross are done to find out the unknown genotypes with the known phenotype. Testcross is done where one parent is known for sure as homozygous recessive. Testcross is based on the Mendel’s law of segregation. Testcross is always performed for a monohybrid cross or for one trait.

Explanation of Solution

Reasons for correct statement:

Testcross has two parents, where one parent is a true-breeding homozygous recessive individual, and the other parent has an unknown genotype but expresses a dominant trait. Testcross helps to determine the genotype of the unknown individual. The unknown genotype can be homozygous dominant or heterozygous. Based on the phenotype expressed by the offspring, the genotype of the unknown parent can be identified.

Option b. is given as “genotypes”.

As genotypes of unknown parents are determined using testcross, option b...