Genome-wide Association Study of Oxidative Phosphorylation in Cocks Semen after Freezing.

The biochemical processes associated with the generation of energy (ATP) - oxidative phosphorylation (OXPHOS) and glycolysis - occupy a central place in the vital activity of cells. OXPHOS is the terminal process of cellular respiration (CR). Aim of the study was Genome-wide Association Study of OXPHOS in cocks sperm after freezing. Semen from 96 cocks was frozen. CR was assessed by the polarographic method. OXPHOS can be evaluated by the reaction CR on adding 2,4-dinitrophenol (2,4 - DNP) to semen sample. 2,4 - DNP disrupt the proton gradient by carrying protons across a membrane and uncouples proton pumping from ATP synthesis because it carries protons across the inner mitochondrial membrane. As a result it increases respiration rate. If the respiration rate increases - there is good OXPHOS. Sperm motility was evaluated by computer-assisted semen analysis (CASA) (ArgusSoft, Russia) before and after freezing. The evaluation was carried out using an Axio Imager microscope (Carl Zeiss Microscopy GmbH, Germany). DNA was isolated from sperm samples for genotyping on Gallus Gallus - Affymetrix Axiom®600k Array. Calculations were performed using the PLINK and EMMAX programs. The Genome-Wide Association Studies (GWAS) was used for the analysis of genomic associations. Results are depicted as ranges, percentages of totals and averages ± SEs. The volume ejaculate varied from 0.4 ml to 1.4 ml, motility before freezing was from 20 to 95% and motility after freezing was from 5 to 80%. The 2.4-DNP (FSRA) stimulation of respiration after freezing ranged from 1 to 8.09, averaging 1.66±0.114. The high repeatability of the FSRA score across samples suggests the presence of genetic factors, the identification of which can serve as a test for selecting animals with sperm whose quality remains fertile after freezing. 28 potential SNPs associated with FSRA the were found. На 5 хромосоме было найден также блок SNPs (большинство из них significant, 4 последних - suggestive: AX-76791596 (P-value=6,20E-09), AX-76791535 (P-value=1,83E-08), AX-76791611 (P-value=1,83E-08), AX-76791454 (P-value=1,87E-08), AX-76791629 P-value=2,11E-08), AX-76791570 (P-value=4,04E-08), AX-76791651 (P-value=5,43E-08), AX-76791640 (P-value=8,84E-08), AX-76791553 (P-value=9,94E-08), AX-76791503 (P-value=1,18E-07), AX-76791443 (P-value=5,49E-07), AX-76791439 (P-value=1,41E-06), AX-76791501 (P-value=1,63E-06). The significant SNPs found were located in the RAG2 gene. We suggest that the polymorphism in this gene is associated with the selectivity of fertilization, and the efficiency the work is associated with ATP-dependent remodeling of ATPase subunits. Studies have opened up the possibility of studying the changes in the cells after freezing. Found SNPs markers will be used to select males whose semen is suitable for cryopreservation.