Polymorphism of histone H1.c' in the population of Muscovy duck (Cairina moschata L.): a link between histone H1.c' allelic variants and ADP-ribosylation of histone H1 subtypes

In this work, a polymorphic variability of Muscovy duck histone H1.c' is presented along with a link of its allelic variants with an extent of ADP (Adenosine Diphosphate)-ribosylation of histone H1 non-allelic subtypes. With the use of a two-dimensional electrophoretic system, histone H1.c' was identified as differentiated into the variously charged isoforms H1.c'1 and H1.c'2. In the population studied, they occur in the form of homozygous phenotype c'1 (frequency 0.384) and c'2 (frequency 0.288) as well as the heterozygous phenotype c'1c'2 (frequency 0.326). Because fewer heterozygotes were observed (0.326) than expected (0.496), the duck population is under inbreeding (F = 0.342, H-I = 0.325) and does not conform to Hardy-Weinberg assumptions (p < 0.05). The total population differentiation (delta = 0.5) and polymorphism information content (PIC = 0.496) show that about half the bird individuals are genetically different in an intermediate diverse population. Because an array of Muscovy duck H1 histones is enriched by the complex LHL (Linker Histone Like), which is a conjugate of histone H1 subtypes with ADP-ribose, its juxtaposition with histone H1.c' allelic variants was examined. This was to uncover a correlation of the phenotype c'2 and c'1c'2 with low intensity of modification (mean LHL density = 316284.9 +/- 47776.7) and the relation of the phenotype c'1 to high modification (LHL density = 1380419.6 +/- 116471.3). A disparity of more than 4 times in the abundance of ADP-ribose linkage indicates a histone H1.c' phenotype-specific association with the level of ADP-ribosylation. It seems that such a difference between histone H1.c' allelic variants might be related to their individual participation in the determination of histone H1 subtype modification status. With respect to this, allelic variants of histone H1.c' may variously influence the ADP-ribosylation reaction, presumably by differentiated stimulation of the enzymes catalysing the histone H1-ADP-ribose linkage.

Automated summary

The study reveals polymorphic variability of the H1.c' histone in Muscovy ducks, with different allelic variants potentially influencing the ADP-ribosylation levels. The population shows signs of inbreeding due to lower observed heterozygotes than expected. Different H1.c' allelic variants exhibit specific associations with ADP-ribosylation levels, suggesting individual roles in determining histone H1 subtype modification status.