DNA packaging of human spermatozoal chromatin

During mammalian spermiogenesis, the majority of the nucleosomes packaging the male haploid genome are replaced by protamines to produce a highly compact chromatin architecture that is critical to male fertility. We have carried out a genomewide survey of human spermatozoal chromatin using both a salt and micrococal nuclease approach to characterise the DNA sequences that remain packaged by histones. Weak salt solutions or limited digestion with micrococcal nuclease facilitates the release of a nucleosome-rich chromatin from mature spermatozoa. Whole genome CGH arrays were used to map the histone and protamine bound portions of spermatozoal DNA.