Shadi Haji Adineh

shajiadinehmail.fresnostate.edu

In most species, mitochondria are maternally inherited. Work in Caenorhabditis elegans has shown that a cellular surveillance system eliminates sperm-borne mitochondria that enter an oocyte. Such a system might have evolved to prevent heteroplasmy (the presence of multiple mitochondrial genotypes in a cell), which can result in mitochondrial disorders. However, in C. briggsae hybrids, repeatedly backcrossing female hybrids to parental males results in male mitochondrial transmission. Observations in other taxa have also shown that hybridization increases paternal mitochondrial transmission, raising the hypothesis that hybrid genotypes cause the surveillance system to malfunction and thus facilitate the increase in paternal transmission. This hybrid dysfunction might occur because of recombination of unknown strain-specific molecular signals of paternal mitochondria and their unknown maternal receptor molecules. To develop C. briggsae as a system for identifying the cellular mechanisms that routinely prevent paternal transmission, my objective was to compare the frequencies of paternal transmission in hybrid and control crosses. Out of twelve novel hybrid lines, three showed the possibility of paternal mitochondrial DNA transmission. This key result motivates future work to identify the genetic architecture of the quality control system responsible for paternal mitochondrial elimination.