We showed by in situ hybridization the dynamic expression patterns of the
opsin subtypes in the zebrafish retina. Expression of red type opsins is
initiated with the shorter-wavelength subtype LWS-2, followed by the longer-wavelength
subtype LWS-1. In the adult retina, LWS-2 was expressed in the central
to dorsal area and LWS-1 in the ventral and peripheral areas. Expression
patterns of green type opsins were similar to those of the red type opsins.
The expression started with the shortest wavelength subtype RH2-1 followed
by the longer wavelength ones, and in the adult retina, the shorter wavelength
subtypes (RH2-1 and RH2-2) were expressed in the central to dorsal area
and longer wavelength subtypes (RH2-3 and RH2-4) in the ventral and peripheral
areas. These results provide a framework for subsequent studies of opsin
gene regulation and for probing functional rationale of the developmental
changes by using the power of zebrafish genetics.