<unk>  is the separation or breaking of DNA strands into pieces. It can be done intentionally by laboratory personnel or by cells, or can occur spontaneously. Spontaneous or accidental<unk>  is<unk>  that gradually accumulates in a cell. It can be measured by e.g. the Comet assay or by the TUNEL assay. Men with sperm motility defects often have high levels of sperm<unk> . The degree of<unk>  in sperm cells can predict outcomes for in vitro fertilization (IVF) and its expansion intracytoplasmic sperm injection (ICSI). The sperm chromatin dispersion test (SCD) and TUNEL assay are both effective in detecting sperm DNA damage. Using bright-field microscopy, the SCD test appears to be more sensitive than the TUNEL assay. Its main units of measurement is the<unk>  Index (DFI). A DFI of 20% or more significantly reduces the success rates after ICSI.<unk>  was first documented by Williamson in 1970 when he observed discrete oligomeric fragments occurring during cell death in primary neonatal liver cultures. He described the cytoplasmic DNA isolated from mouse liver cells after culture as characterized by DNA fragments with a molecular weight consisting of multiples of 135 kDa. This finding was consistent with the hypothesis that these DNA fragments were a specific degradation product of nuclear DNA.
DNA fragmentation
DNA condensation
DNA laddering
DNA replication stress
DNA adduct
Cell damage
Cell death
Protein carbonylation