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The phenomenon of nucleosome retention in mammalian sperm chromatin is still not clarified yet. The goal of our study was to characterize the binding sites of sperm nucleosomes in the human and bovine genomes, and through this, to clarify whether nucleosome retention in sperm underlies rules of great generality and has a biological function. Comparing two mammalian systems we found that nucleosomes remain mainly in centromeres and in non-coding intergenic and intron regions. In contrast, coding DNA, promoter regions and transcription start and end sites, especially in homeobox genes and in the majority of genes with relevance for organ development and morphogenesis, were nucleosome-free.Overall design: 146 bp mono-nucleosomal DNA was isolated and purified from sperm samples of two fertile bulls (bos taurus), one fertile man and a pool of four fertile donors; each DNA sample was deep sequenced using Illumina GAIIx and genome-wide mapped on respective genome; nucleosome-binding sites were analyzed in a genome-wide comparative manner. |