Expression of feather β-keratins during embryonic feather development. This figure summarizes the present data on the expression of feather β-keratin by chromosomal location in embryonic (day 17 down and wing feathers) feathers using data from the present study. For each feather type (Day 17 down, Day 17 Wing), the chicken (GALGA) chromosome number of the feather β-keratins expressed is listed. The feathers of day 17 dorsal skin express feather β-keratins located on GALGA chromosome 1, 6, 10, 25 (both feather and feather-like β-keratins) and chromosome unknown. Wing feathers, at day 17, express feather β-keratins from GALGA chromosome 6, 10, 25 (both feather and feather-like β-keratins) and chromosome unknown.