Evidence on the stability of histone H1.a polymorphic variants during selection in quail

Abstract

The goal of this work was to check whether selection for quantitative traits may cause a change in the histone H1 allelic complement and whether it can therefore be considered a modulator of histone H1-dependent chromatin functioning. For this purpose, a fluctuation of histone H1.a polymorphic variants was analyzed among a non-selected (control) quail line and the line selected for a high cholesterol content in the egg yolk. The histone H1.a was found to be polymorphic due to its differential migration rate in the AU-PAGE (acetic acid–urea polyacrylamide gel electrophoresis). Based on this, two H1.a isoforms (H1.a1 and H1.a2) that form three phenotypes (a1, a2 and a1a2) were distinguished in the quail lines tested. A comparably expressed (p > 0. 05) and low relative variable (coefficient of variation, CV < 0. 25) histone H1.a phenotypes were in agreement with Hardy–Weinberg equilibrium (HWE) in both the non-selected (χ2 = 1. 29, p = 0. 25) and selected (χ2 = 1. 9, p = 0. 16) quail line. The similarity among quail lines was assessed based on the equal distribution of histone H1.a phenotypes (χ2 = 1. 63, p = 0. 44) and alleles (χ2 = 0. 018, p = 0. 89) frequency in both quail lines tested. This indicates that selection does not affect the histone H1.a polymorphic variants. The stability of histone H1.a during selection might suggest that likely chromatin processes coupled to the selected trait are not linked to the activity of histone H1.a.