Assessment of sperm nucleus integrity in infertile men: a novel research field for anthropology in the molecular era.

Anthropology has always been particularly interested in the origin of human life and the development towards adulthood. Although originally working with skeletal measurements and bio-morphological markers in modern populations, it has now entered the growing field of applied molecular biology. This relatively recent advance allows the detailed study of major events in human development and senescence. For instance, sperm DNA integrity and chromatin re-organization are crucial factors for fertilization and embryo development. Clinical researchers have developed improved methods for the evaluation of DNA integrity and protaminosis in sperm nuclei, such as the TUNEL and the CMA3 assays. DNA damage in spermatozoal nuclei is detected using the TUNEL assay which depends on the specific enzymatic reaction of TdT with the end strand breaks of DNA. Protaminosis in spermatozoal nucleus is evaluated using CMA3 assay, which is based on the in situ competition between CMA3 and protamines. Such measurements may provide useful data on human reproductive health, aiding the explanation of demographic differences across the world.