The habitats of two brush lizards that reside in Arizona, U. ornatus and U. graciosus, overlap and a hybrid species has arisen over time that has the nuclear DNA from one introgressed with the mitochondrial DNA from the other. Previous studies by Haenel and Del Gaizo Moore have shown that the mitochondria in these hybrid lizards are much more inefficient than those in the two parental species. It was observed that all three species of lizards have internal melanin in their livers, with the hybrids possessing much higher amounts. One hypothesis explaining the higher melanin content in the hybrid’s livers is that it helps protect their inefficient mitochondria from oxidative stress. In order to test this hypothesis, we sought to induce expression of melanin in liver cells using 1,2-dimethyl-3,3-butanadiol (1,2DM-3,3BD). Initially, human epithelial kidney (HEK) cells were treated with 12.5-37.5 mM of 1,2DM-3,3BD for 6 days and their capacity to resist oxidative stress was tested using a CellROX and cell viability flow cytometry assay. Melanin induction in HEK cells was small and therefore no protection was afforded against oxidative stress. Next, a protocol was developed to isolate primary liver cells from North Carolina tree lizards. Currently, different methods are being tested to maintain these primary cell cultures long enough to treat it with 1,2DM-3,3BD to determine if melanin expression can be induced in the cells.
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Funded with grant-in-aid from Elon University and the endowed Glen Raven grant
