Sharu Paul Sharma - PhD Preliminary Exam

Wednesday, April 10, 2019 - 1:00pm to 3:00pm

Major Professor:  Dr. Thomas Peterson

Home Department:  GDCB

Title of Defense:
   Transposon-induced inversions activate tissue specific gene expression in Maize

   Structural rearrangements of genome caused by DNA transposons such as Activator (Ac) element can have considerable biological impacts such as disrupted gene function, change in gene expression, or formation of chimeric genes. We studied the molecular structures of genomic rearrangements caused by alternative transpositions of Ac/fAc elements inserted in or near the p1 and p2 genes on chromosome 1. The p1 gene encodes a Myb-type transcriptional regulator of flavonoid pigmentation in kernel pericarp and cob glumes; p2 is a linked paralogous gene that is expressed in anther and silk, but not kernel pericarp and cob. We have isolated an allele termed p1-wwB54 in which p1 is partially deleted while p2 is intact; the kernel pericarp is white with infrequent red sectors. From p1-wwB54, we identified 19 independent inversions that change the position of a p1 enhancer and activate expression of p2 in the kernel pericarp, resulting in red kernel color.