Q1. Consider a dominant pure-breeding parent pea plant that had green peas, was tall, and had purple flowers, which was crossed with a recessive pure-breeding parent that had yellow peas, was short, and had white flowers. In order to produce a gene map, Ice Spice selects a single F1 heterozygote offspring and test crosses it to produce 80 F2 offspring that collectively exhibit eight different phenotypes with 10 babies presenting with each phenotype. Can she automatically assume that the three genes in the pea plants were linked? Explain your answer.
Q2. What if the 80 offspring that were produced by Ice's experiment instead contained 42 F2 offspring that have green peas, tall stalks, and purple flowers, and 38 of the reciprocal phenotype, yellow peas, short stalks, and white flowers. Would she be able to say the three genes were assorting independently of one another? Explain your answer.
Q3. Use X2-analysis to check your data if you have time. Include your chi-square analysis math here with an appropriate conclusion statement*. Follow the same statement format for the X2 solution that was given to you in the corn cob lab and amend accordingly. Be cognizant of how you posit your hypothesis in relation to the p-value returned from your X2-analysis. You should be positing a null hypothesis of 'no difference'. What ratios would be expected for a trihybrid cross? In a case involving dominant and recessive traits, the F2 ratio would approximate 27:9:9:9:3:3:3:1 if two heterozygotes were used in the F1 cross; since this lab is about test crossing, a 1:1:1:1:1:1:1:1 ratio is the expected outcome.
Q4.In a few sentences, explain what it means for genes to be linked.