IN GARDEN PEAS, THE ALLELE FOR TELLOW PEAS IS DOMINATE T OTHE ALLELE FOR GREEN PEAS. SUPPOSE YOU HAVE A PLANT THAT PRODEUCES YELLOW PEAS, BUT YOU DON'T KNOW WHETHER IT IS HOMOZYGOUS DOMINANT OR HETEROZYGOUS. WHAT EXPERIMENT COULD YOU DO TO FIND OUT?
Sheesh 12 years and still no answer- :|
To determine whether the plant producing yellow peas is homozygous dominant (YY) or heterozygous (Yy), you can perform a test cross.
Here's how to do it:
1. Select a true breeding green pea plant (yy) as the other parent for the test cross. This means you need to choose a plant that only produces the green pea phenotype when self-fertilized.
2. Cross-pollinate the yellow pea plant (unknown genotype) with the green pea plant. It can be done by transferring pollen from the anther (male reproductive organ) of the green pea plant to the stigma (female reproductive organ) of the yellow pea plant.
3. Allow the cross-pollinated yellow pea plant to self-fertilize or grow fruits containing seeds.
4. Observe the phenotype of the offspring peas. If all the seeds produce yellow peas, it indicates that the yellow plant is homozygous dominant (YY). This is because the green plant can only contribute the recessive allele (y), and if the dominant allele (Y) is present in the yellow plant, all the offspring will have the yellow phenotype.
5. If some of the offspring peas produce green peas, it indicates that the yellow plant is heterozygous (Yy). In this case, the yellow plant can pass either the dominant allele (Y) or the recessive allele (y) to its offspring. Thus, the presence of both yellow and green peas in the offspring suggests that the yellow plant is heterozygous.
By performing this test cross, you can determine whether the plant producing yellow peas is homozygous dominant (YY) or heterozygous (Yy) based on the phenotype of the offspring.