Graduation Year


Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Findley Finseth

Reader 2

Allison Abbott

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© 2018 Julia A Theiss


microRNAs are single-stranded small RNAs that function as post-transcriptional regulators of gene expression. We are studying the mir-44 family, specifically mir-44 and mir-45, which have identical sequence. Loss of mir-44 and mir-45 results in defects that suggest that the mir-44 family acts to negatively regulate the MAPK pathway. The MAPK pathway regulates sex myoblast migration, a process which is required for normal egg laying. We hypothesized that the mir-44 family of microRNAs is necessary for normal sex myoblast migration and subsequent formation of the functional egg laying structure in the hermaphrodite. We created a mutant that had mutations in both mir-44 and mir-45 and a transgene that expresses GFP in the sex myoblast cells. Then we observed the migration and division of the sex myoblasts in wild-type and mutant worms using fluorescence microscopy. In all cases, the mutant worms displayed a greater percent difference from average sex myoblast migration and division. However, a two-tailed two-proportions z-test found no significant difference between wild type and mutant sex myoblast migration (p=0.9148), nor in mutant sex myoblast division along the axial (p=0.4205) and sagittal (p=0.3583) planes of the body. This allows us to conclude that mir-44 and mir-45 are unlikely to be responsible for the migration nor division of the sex myoblasts, and the defects are likely due to interference with a different biological mechanism.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.