Analysis of Circulating DNA Distribution in Pregnant and Nonpregnant Dairy Cows1

Abstract

Circulating nucleic acids (CNAs) are free-floating, cell-free DNA and RNA molecules in the circulation of healthy and diseased humans and animals. The aim of this study was to identify differences in CNA distribution in serum samples from multiparous pregnant (n = 24) and nonpregnant (n = 16) dairy cows at different days of gestation (Days 0, 20, and 40). A modified serial analysis of gene expression procedure was used to generate concatemerized short sequence tags from isolated serum DNA. A total of 6.1 × 10(6) tags were recovered from analyzed samples (n = 40). Significant differences between the pregnant and nonpregnant groups were detected in chromosomal regions, protein-coding sequences, and single genes (P < 0.05). Approximately 23% (1.4 × 10(6) tags) of the total sequence pool were present exclusively in the analyzed serum samples of pregnant cows. Of these tag sequences, seven originated from genomic regions and 13 from repetitive elements. Comparative BLAST analysis identified the repetitive tags as BovB (non-long terminal repeat retrotransposons/long interspersed nuclear elements), Art2A, BovA2, and Bov-tA2 (short interspersed nuclear elements). To our knowledge, this is the first study to comprehensively characterize the circulating, cell-free DNA profile in sera from pregnant and nonpregnant cows across early gestation.

Biochemical parameters, dynamic tensiometry and circulating nucleic acids for cattle blood analysis: a review

“…In addition, the diagnostic utility of CNAs has been shown in cattle and elk with bovine spongiform encephalopathy (Gordon et al, 2009). The analysis of cfDNA in domestic animals has been reported in several studies demonstrating cfDNA as useful markers in diagnosis (Beck et al, 2009(Beck et al, , 2013Brenig, Schütz & Urnovitz, 2002;Gordon et al, 2009;Mayer et al, 2013aMayer et al, , 2013bSchütz et al, 2005).…”

Extraction and Elevation of Cell-Free DNA under Mastitis and Heat Stress in Dairy Cattle

“…A recent study in dogs reported an increased level of cfDNA in neoplastic dogs compared to the ones without neoplasia, and among all the neoplastic cases, the concentration of cfDNA in the lymphoid neoplasia group was significantly higher [20]. In cattle, it was found that there were some different sequence tags in the serum between pregnant and non-pregnant dairy cows at different stages, and the distribution of cfDNA was significantly different [21]. Research about the diagnosis of bovine pregnancy showed that cfDNA could be used as a marker to detect early pregnancy in cattle [22].…”