 UCSD
biologists recently discovered that a key protein in the compound
eyes of the fruit fly allows the formation of distinct light-gathering
units in each of its 800 unit eyes. This evolutionary change to an “open
system” enabled insects to make significant improvements in
vision. In contrast, beetles, bees and many mosquito species have
the light-gathering units fused together into a “closed system.”
The scientists report in a recent issue of Nature that one of three
proteins needed to form these light-gathering units is present in
the visual system of fruit flies, house flies and other insects with
open-eye systems, but conspicuously absent in species with closed
systems. The research team, headed by Charles Zuker, a professor
of biology and neurosciences, also showed that the loss of this protein,
called “spacemaker,” can convert the eyes of fruit flies
from an open-eye system into a closed one. In contrast, the introduction
of the protein into
a closed-eye system can transform it into an open one.
“These results help illustrate the beauty and power of
evolution,” says Zuker, “and show how ‘little steps’… can
so spectacularly account for major changes in form and function.” 
Contributors to Making Waves: Mario Aguilera, '89, Rex Graham, Raymond Hardie, Debra Kain, Daniel B. Kane, Kim McDonald
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