Linked Genes Tend to Stay Together
Because the Red trait and Plump trait are not always found together, one gene cannot be responsible for both traits. The occurrence of the recombinant Red, Shrunken and White, Plump testcross offspring eliminates the possibility of something like pleiotropy. Can we still use linkage as an explanation, though? Yes, if we think through chromosome behavior during meiosis, we can see why genes on the chromosome tend to stay together but will not always be passed on together. Let's think about meiosis and crossing over to understand these results.