Distribution of non-allelic histone H1 subtypes in five avian species

The arrays of histone H1 subtypes from five avian species (chicken, grey partridge, pheasant, quail and duck) were compared to evaluate their intra- and inter-species variability. The electrophoretic patterns of linker histone preparations revealed the presence of subtypes that occur in all species (H1.a, H1.b, H1.c, H1.c′, H1.d and H5) and those which are confined to some species only (H1.a′, H1.b′, H1.z). In the densitometric profiles of histone H1 bands resolved in one-dimension acetic acid-urea polyacrylamide gel, the quantitative differences were observed both within a species (the ratio of H1.b to H1.d = 8.13 in quail) and between species (the ratio of H1.d in grey partridge and quail = 8.37). The comparable levels of abundant histone H5 that constitute from 53.62% (quail) to 60.86% (duck) of whole linker histone complement were detected in all species. Likewise, the quantification of H1 protein spots separated in a two-dimension SDS-polyacrylamide gel indicated that their intensity ratios could vary up to about 17-fold within a species (the ratio of H1.d to H1.a′ in grey partridge) and up to 10-fold between species (the ratio of pheasant H1.d to quail H1.d). Differences (P<0.05) in the histone H1 subtype levels were found both within and between avian species. A low to moderate range for the coefficients of H1 spot variation (from 0.13 to 0.72) was obtained for several independent histone H1 preparations.