Genetic integrity and epigenetic perspective

1 Maintenance of genetic integrity and variability after cell banking 

The impact in future offspring of fertilization with an injured DNA genome needs careful study. Many cells, and particularly oocytes, have the ability to repair DNA failures using specific pathways according to the nature of the insult (for example, simple or double strand breaks, base modifications, and base mismatch). The activation of these mechanisms has been noted in oocytes fertilized with frozen DNA cryodamaged sperm (Kopeika et al., 2004 Perez-Cerezales et al., 2010b), but this ability is limited and could introduce changes to the code, for which potential consequences should be evaluated. 

Oxidative stress is always perceived to be the most harmful factor for DNA. In fact, the increase in ROS production during cryopreservation, mainly due to damaged mitochondria and acrosomes, has been observed by several authors in mammals. In fish, the presence of oxidized bases (oxo-cytosine and oxo-guanosine) has been reported in rainbow trout sperm subjected to cold storage (4°C) and cryostorage (Perez-Cerezales et al, 

The use of antioxidants in the extender is being optimized to reduce cryoinjuries chromatin integrity was very much improved when the low-density lipoprotein fraction of egg yolk (LDL) was added to the freezing extender (Perez-Cerezales et al, 2010a). 

Another challenge is to understand how DMSO could affect DNA 

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