Semi-quantitative detection of human sperm nucleoprotein maturation Under normal conditions, the basic proteins (nucleoproteins) bound to the DNA of the sperm nucleus will undergo a natural maturation process from histones to ichthyospermins. This gradual replacement of histones by ichthyospermins is called sperm nucleoprotein histotype transition, and this histotype transition is of physiological importance. The sperm nucleus carries all the genetic information from the father, and these genes must begin to be expressed after fertilization. Prior to fertilization sperm genes are tightly concentrated under the special protection of fisetin without any DNA transcriptional effect. However, abnormal nucleoprotein histotype conversion can cause male infertility or early embryonic abortion by: (1) sperm DNA is unstable and easily damaged, making fertilization difficult; (2) once fertilized, sperm nuclei do not depolymerize normally due to abnormal nucleoprotein histotype, thus affecting the fusion of male and female progenitors; (3) embryos do not develop normally, resulting in aborted embryos. Reference value Normal reference value: nucleoprotein immature sperm ≤ 30%