Fatores de correção para ganho de peso médio diário no período do nascimento ao desmame em bovinos da raça Nelore

The objective of this work was to calculate correction factors for the effects of age of the dam (AOD), age of the calf (AOC) and Julian birth date (DOB) on the average daily gain (ADG) from birth to weaning period of animals of Nellore breed. The data were analyzed by restricted maximum likelihood, using the animal model. The model included the fixed effects of contemporary group (CG), AOD, AOC and DOB, and the direct effects (animal), maternal, permanent environmental and residue. The data were submitted to previous analysis for the definition of segmented polynomials to be used by means of SAS computing program where the covariates sets were created. In the ADG study in function of AOD, was observed a quadractic-quadractic effect, and the dams reached the maturity between the 5 th and 7 th years of age. The predicted ADG for the calves increased for the dams in the 4 th and 6 th years of age, as that the maximum gain was reached, decreasing from 6 up to 15 years of age, when the calves presented the lower gain rate. For AOC was observed a simple quadratic effect. The ADG presented an overall mean of .681 kg/day and decreased as the animal age increased (from 156 th to 308 th day of age). The Julian birth date showed a linear effect on the ADG, that decreased in the period from 220 th to 365 th day of the Julian calendar. These two effects (AOC and DOB) were the most difficult to model: the knots and the segments of obtained polynomials at each step were dependent and, or influenced by the used modeling for the other effects, suggesting multicolinearity problems and, or concentration of data in influent points. In function of these problems, a simplified modeling of the AOC and DOB effects was choose.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Instituto de ZootecniaDepto. Zootecnia - Melhoramento G. FCAV UNESP, Jaboticabal, SPCNPqS/C Ltda.FAPESPDepto. Zootecnia - Melhoramento G. FCAV UNESP, Jaboticabal, S

Placental hydroxymethylation vsmethylation at the imprinting control region 2 on chromosome 11p15.5

In addition to methylated cytosines (5-mCs), hydroxymethylcytosines (5-hmCs) are present in CpG dinucleotide-enriched regions and some transcription regulator binding sites. Unlike methylation, hydroxymethylation does not result in silencing of gene expression, and the most commonly used methods to study methylation, such as techniques based on restriction enzymatic digestion and/or bisulfite modification, are unable to distinguish between them. Genomic imprinting is a process of gene regulation where only one member of an allelic pair is expressed depending on the parental origin. Chromosome 11p15.5 has an imprinting control region (ICR2) that includes a differentially methylated region (KvDMR1) that guarantees parent-specific gene expression. The objective of the present study was to determine the presence of 5-hmC at the KvDMR1 in human placentas. We analyzed 16 third-trimester normal human placentas (chorionic villi). We compared two different methods based on real-time PCR after enzymatic digestion. The first method distinguished methylation from hydroxymethylation, while the other method did not. Unlike other methylation studies, subtle variations of methylation in ICRs could represent a drastic deregulation of the expression of imprinted genes, leading to important phenotypic consequences, and the presence of hydroxymethylation could interfere with the results of many studies. We observed agreement between the results of both methods, indicating the absence of hydroxymethylation at the KvDMR1 in third-trimester placentas. To the best of our knowledge, this is the first study describing the investigation of hydroxymethylation in human placenta using a genomic imprinting model

Variation in DNA methylation in the KvDMR1 (ICR2) region in first-trimester human pregnancies

Stem cells & developmental biolog