Fig. 8. Quantitative analyses of cell death when Fms activity is curtailed. (A) Mean (+95% confidence intervals) numbers of TUNEL⁺ cells observed in trunk neural crest migratory pathways of 24-28 h embryos (n=128) maintained either at 24°C, transferred during these stages of neural crest migration from 24°C to 33°C for 2-3 hours, or maintained at 33°C. A dramatic increase in TUNEL⁺ cells occurs in fms^174A homozygous embryos exposed to the 33°C restrictive temperature, as compared to fms^174A homozygotes at 24°C or heterozygotes at either temperature (genotype x temperature interaction for square root-transformed data: F_2,122=10.0, P<0.0001). (B) Mean numbers (+95% confidence intervals) of xanthophore pigment-containing exclusion bodies in caudal fins of adults (n=14) maintained either at 24°C or transferred from 24°C to 33°C for 3 days. A sharp increase in the numbers of such exclusion bodies occurs in fms^174A individuals transferred to 33°C as compared to fms^174A maintained at 24°C or wild-type individuals transferred from 24°C to 33°C (square root-transformed data, F_2,11=28.04, P<0.0001).