GFP expression pattern of olvas-GFP transgenic medaka This transgenic strain contains 5 kb upstream region and 0.7 kb 3′-UTR of medaka vasa gene. The expression of GFP is restricted in germ cells. The image is 1-dph larva. A and C are bright light images. B and D are fluorescent images. The bars in A and C represent 1 mm and 0.1 mm, respectively. Yellow spots are the autofluorescence of leucophores.