Figure 4.

Analysis of boundary function of mouse tyrosinase LCR sequences in transgenic D.melanogaster. Protection from chromosomal position effects of mouse tyrosinase LCR sequences was carried out in transgenic flies using the white minigene assay. Top, fly heads, from reference white mutant stock along with representative transgenic individuals for yellow, pale orange, orange, brown and red eye colours are shown. Pictures are taken in air from anaesthetised animals. Percentage of red-pigment in eyes from each category, established by colorimetric methods (57), is indicated (100% = wild-type flies). The average amount of red-eye pigment within each line was estimated taking into account the percentage of individuals from a given colour observed within each line. Mean values of red-pigment content in eyes for each independent transgenic line are depicted graphically as single bars using a logarithm scale (y axis), because most of the perceived eye colour variability takes place below 10% of wild-type pigment level. Phenotypic evaluation of transgenic flies is shown in heterozygous (grey bars) and homozygous (black bars) individuals. A total of 86 transgenic fly lines are shown, grouped per construct and distributed as follows: 14 lines for ‘w’ (A and B); 11 for BRwBR (C and D); 11 for 5′HS4w5′HS4 (E and F); 13 for TE3wTE3 (G and H); 7 for XwX (I and J); 8 for HSwHS (K and L); 12 for LCRwLCR (M and N); and 10 for LCRmutwLCRmut (O and P). In addition, the overall means and standard deviations (SD) for all lines analysed within each construct are depicted as white bars and are also presented, without logarithm transformations, in Table 1.