BIOL 200 Lecture Notes - Lecture 10: Retrovirus, Retrotransposon, Coding Region
Document Summary
Corn color variegation (unexpected!) from crossing purple (c/c or c/c) with yellow (c/c) -> since in corn, genetic inheritance is independent for each kernel! (each kernel = an embryo from a diff. egg) The 2 loci involved in breakage: ds (dissociation), ac (activator) Ac can activate chromosome breakage at ds --> an acentric fragment is lost. Where breakage happens, that part of the corn becomes yellow, the rest (with no ds breakage) remains purple c/c could revert to c/c. this process also requires ac. Two possibilities: either ds jumps back out (w/ help from ac), or ac jumps out on its own. Breakage at ds means the acentric fragment is lost, along with it c gene is lost, hence failure to express purple color gene. Ds was on the same chromosome as c gene. Yellow color could also due to c-ds link (alternative to breakage). So mcclintock proposed that both ac and ds are mobile.
