Mitochondrial DNA single nucleotide polymorphism associated with weight estimated breeding values in Nelore cattle (Bos indicus)

We sampled 119 Nelore cattle (Bos indicus), 69 harboring B. indicus mtDNA plus 50 carrying Bos taurus mtDNA, to estimate the frequencies of putative mtDNA single nucleotide polymorphisms (SNPs) and investigate their association with Nelore weight and scrotal circumference estimated breeding values (EBVs). The PCR restriction fragment length polymorphism (PCR-RFLP) method was used to detect polymorphisms in the mitochondrial asparagine, cysteine, glycine, leucine and proline transporter RNA (tRNA) genes (tRNAasn, tRNAcys, tRNAgly, tRNAleu and tRNApro). The 50 cattle carrying B. taurus mtDNA were monomorphic for all the tRNA gene SNPs analyzed, suggesting that they are specific to mtDNA from B. indicus cattle. No tRNAcys or tRNAgly polymorphisms were detected in any of the cattle but we did detect polymorphic SNPs in the tRNAasn, tRNAleu and tRNApro genes in the cattle harboring B. indicus mtDNA, with the same allele observed in the B. taurus sequence being present in the following percentage of cattle harboring B. indicus mtDNA: 72.46% for tRNAasn, 95.23% for tRNAleu and 90.62% for tRNApro. Analyses of variance using the tRNAasn SNP as the independent variable and EBVs as the dependent variable showed that the G -> T SNP was significantly associated (p < 0.05) with maternal EBVs for weight at 120 and 210 days (p < 0.05) and animal's EBVs for weight at 210, 365 and 455 days. There was no association of the tRNAasn SNP with the scrotal circumference EBVs. These results confirm that mtDNA can affect weight and that mtDNA polymorphisms can be a source of genetic variation for quantitative traits

Cumulative Risk, Emotion Dysregulation, and Adjustment in South African Youth

Research on cumulative risk is growing, however, little work has occurred in low- or middle-income countries, and few studies have focused on processes linking risk to outcomes. This study explored relations between components of cumulative risk and adjustment in a sample of 324 South African youth (M age = 13.11 years; SD = 1.54 years; 65% female; 56% Black/African; 14% Colored; 23% Indian; 7% White), and tested competing models of emotion dysregulation as a mediator or moderator of risk-adjustment links. Data was collected from youth and their female caregivers during home interviews. Structural equation models and regression analyses accounting for age and sex contributions revealed that emotion dysregulation mediated associations between sociodemographic risk and internalizing symptoms, externalizing problem behavior, and drug use severity, and moderated links between psychosocial risk and internalizing symptoms and externalizing problem behavior. For the mediator models, sociodemographic risk was associated with impaired emotion regulation, which in turn was linked with heightened adjustment difficulties. For the moderator models, psychosocial risk was linked with adjustment problems only when emotion dysregulation was high. These data indicate the importance of disentangling components of cumulative risk. Future research within the South African cultural context might build on these findings by adapting and testing school- or family-based prevention or intervention programs that include modules on emotion regulation