This study was undertaken to show whether chromatin phenotype(s) related to histone H1 polymorphism(s) exhibit connection with breeding practice (selection for reduction of body mass) and/or physiological trait (withdraw of the food) of the organism. For this purpose, a genetic diversity between quail lines selected for high and low reduction of body mass after transient food withdrawal was examined using variation in the histone H1 allelic expression. Symmetric and asymmetric expression of the isoforms of histone H1.b and histone H1.d was identified in 2-D PAGE due to various molecular weight and different intensities, respectively. Low (locus H1.d) to moderate (locus H1.b) differentiated populations conform to Hardy-Weinberg equilibrium but distribution of the phenotypes significantly differ between them. Whereas frequency of the same phenotype of histone H1.b is different between selected lines, the frequency of the same phenotypes of histone H1.d is similar in both selected lines. Thus, line-specific promotion of the phenotypes of histone H1.b suggest a response to conducted selection. Unlike this, a line-nonspecific arrangement of the phenotypes of histone H1.d appear due to the stress evoked by food withdrawal ongoing during the selection. Such a result indicate that histone H1 allelic variants possess individual impact on chromatin states and/or processes associated with breeding practices and physiological conditions of the organism. According to this, functional individualization is a characteristic feature of histone H1 polymorphic variants.