In situ hybridization experiments showing csf1ra expression in cichlids. (a-d) In male Astatotilapia burtoni (a), which typically have more than 10 egg-spots arranged into two or more rows (b), we could detect csf1ra expression in the forming (c) as well as in the growing egg-dummies (d; the position of the yellowish inner circle, ic, and the transparent outer ring, tr, is indicated). Note that the yellow pigments of the egg-spots are removed during tissue processing. (e-h) In male Pseudotropheus sp. 'bicolor' (e), for which we used a morph with only one egg-spot (f), csf1ra expression was detected throughout the entire egg-spot (g), and it appears that the dark melanophores arrange around the center of csf1ra expression (h), just as reported for zebrafish, where csf1ra is indirectly also responsible for melanophore organization . (i-l) In male Thoracochromis brauschi (i), csf1ra is expressed in the yellow blotches of the anal fin (j, k), and also in the pearly spots ('Perlfleckmuster') on the posterior part of the anal fin (l). (m-p) In the basal riverine haplochromine Pseudocrenilabrus multicolor (m), the male anal fins do not exhibit egg-spot like blotches (n) and no csf1ra expression could be detected either (o, p). (q-u) csf1ra is expressed in the yellowish/orange areas of the pearly spot pattern on the dorsal fins of male A. burtoni (q-s) and P. multicolor (t, u). (v-z) csf1ra is expressed in the egg-dummies on the tassels at the tips of the conspicuously elongated pelvic fins of the ectodine cichlid Ophthalmotilapia ventralis (v-x). Female fins of O. ventralis (y) do not show csf1ra expression (z). The control experiments show that csf1ra is not expressed in female anal fins or in the "sense" control. Arrowheads refer to identical points in sequential images.