Richard Jimenez became fascinated with the mitochondrial genome through a forensics biology seminar in the Spring of 2004. His interest in the inheritance, importance and applications of mitochondrial DNA took him to the lab of Dr. Procaccio, where he has been conducting research since the Fall of that year. Over that time, he has enjoyed building personal relationships with others in the lab, especially his mentors. He hopes to use the critical skills he has learned through research to pursue his goal of becoming a veterinary scientist. In his spare time, Richard enjoys boogie boarding, running, and spending time with friends and family.

Mitochondria are organelles that produce essential energy for cellular function. Each mitochondrion contains multiple copies of a small circular piece of maternally inherited DNA called mitochondrial DNA (mtDNA). MtDNA mutations cause many known mitochondrial diseases, which can be diagnosed from a muscle biopsy. A common mtDNA mutation at position 3243A>G can cause diabetes at low levels of mutation, and a severe neurological disease at higher levels. Conventional techniques used to detect this 3243A>G mutation overlook its presence at low levels, and we sought to assess an alternate technique that might improve the detection sensitivity and throughput of mtDNA mutations. Our technique is based on the use of the Transgenomic WAVE System for the HPLC-mediated analysis of mutation-specific restriction fragments derived from PCR products. This was derived through analysis of blood samples from patients who possibly carried the mutation. Our technique found that several patients carried the 3243A>G mutation, while conventional techniques, such as sequencing, overlooked its presence. Our study suggests that this sensitive technique can accurately diagnose a carrier of a mtDNA mutation without the use of a painful muscle biopsy, even when the mutation is present at low levels. The use of this technique may help reassess the prevalence of the 3243A>G mutation in the diabetic population.

Vincent Procaccio School of Medicine

Energy is provided to cells by structures known as mitochondria, each of which contains multiple copies of a piece of DNA called mitochondrial DNA. Individuals may suffer from a condition known as mosaicism or heteroplasmy, in which normal and abnormal mitochondria can exist within the same cell or tissue. Richard Jimenez’s project in our laboratory was to improve the detection level of mitochondrial DNA mutations in blood samples from diabetic patients. A more sensitive detection tool might be an effective method to screen populations for mitochondrial disorders, with significant potential clinical implications. It could also be used to examine the presence of mitochondrial DNA mutations in cancer cells. Richard’s work shows the opportunities faculty-mentored undergraduate research offers for students to gain experience and apply the theoretical concepts they learned in class.