Tiny, tiny baby mouse. How cute.

When I say baby, what I really mean is embryo. This 18.5-day-old double transgenic mouse embryo (transgenic simply meaning that it contains genes from another species) was taken by Gloria Kwon and it won 1st place in the annual Nikon Small World photomicrography competition back in 2007.

photo by Gloria Kwon, copyright of Nikon Small World

The image was taken at 17x magnification. The green that you see is the in-tact yolk sac with green fluorescence  The rest of the embryo, including the placenta, have red fluorescence.

The image was taken using widefield microscopy with various lighting conditions under brightfield as well as green and red fluorescent filters in darkfield which enable her to show up details of the embryo that would be difficult to see or document otherwise.