Pigmentation Pattern Formation in Spotted and Striped Zebrafish
Matilda Omoru
Alicia Coughlin
Jennifer O. Liang
Abstract
We examined the development of striped and spotted pigmentation by comparing and contrasting wildtype zebrafish (striped) with fish carrying the leopard mutation (spotted). We hypothesized that WT and leopard mutant fish would differ in pigmentation during larval and juvenile stages. Surprisingly, we found that the pigment formed similar complex but ordered patterns in both WT and leopard mutant zebrafish early in development. After seven to eight days of fertilization, both types of zebrafish had lines of dark pigment cells called melanocytes on their dorsal, ventral and lateral sides. Some zebrafish had two lines in the lateral side while others had one. Further, both WT and leopard mutant fish looked the same after four weeks of development. At week seven, the WT and leopard fish looked different. Both strains had two lines along the lateral sides. However, in the WT fish, the lines of melanocytes were contiguous and defined. In the leopard mutant fish, the lines had gaps with no black pigment between cells or groups of cells. Between week seven and adulthood (week eight and beyond), lines in the leopard mutants gradually disappeared and were replaced by spots.
