Monohybrid Cross Problem Set

Problem 7: The test cross

To identify the genotype of yellow-seeded pea plants as either homozygous dominant (YY) or heterozygous (Yy), you could do a test cross with plants of genotype _______.

Tutorial

Test cross with yy

Although the unknown genotype could also be determined by a cross with a known heterozygote, test crosses are done with homozygous recessive individuals. If the unknown is heterozygous, the recessive trait will be present in half of the offspring.

The Biology Project
Department of Biochemistry and Molecular Biophysics
University of Arizona
Thursday, October 1, 1998
Revised: November 2004
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