RESUMO
This study estimated the genetic variability and correlations between growth and reproductive traits in Nelore cattle. Annual genetic changes in female reproductive traits were also evaluated using repeated measures. Direct heritability was moderate for the growth traits and scrotal circumference (0.235⯱â¯0.015 to 0.443⯱â¯0.006), indicating genetic variability in these traits in the population studied. Maternal heritability was low for weaning height (0.042⯱â¯0.012) and weaning weight (0.112⯱â¯0.013). Regarding female reproductive traits, gestation length (GL) exhibited a slightly higher heritability (0.179⯱â¯0.006) than days to calving (DC) and calving interval (CI) (0.123⯱â¯0.006 and 0.105⯱â¯0.008, respectively). Repeatability was lower for GL (0.222⯱â¯0.006) compared to DC (0.318⯱â¯0.004) and CI (0.406⯱â¯0.006). Moderate and positive genetic correlations were obtained between the growth traits and scrotal circumference, ranging from 0.193⯱â¯0.019 to 0.519⯱â¯0.007. Weaning height showed low and positive genetic associations with GL (0.138⯱â¯0.007) and CI (0.189⯱â¯0.016), but was not correlated with DC (-0.016⯱â¯0.011). Similarly, weaning weight, yearling height or yearling weight was not associated with any of the female reproductive traits. The genetic correlations between scrotal circumference and female reproductive traits were negative and favorable, but low: -0.116⯱â¯0.020 (GL), -0.084⯱â¯0.028 (DC), and -0.054⯱â¯0.038 (CI). Favorable genetic associations were estimated between all female reproductive traits, ranging from 0.170⯱â¯0.040 to 0.442⯱â¯0.050. Genetic changes were favorable for GL and CI (-0.02 days/year and -0.11 days/year, respectively) and unfavorable for DC (0.16 days/year). In conclusion, selection for higher growth using the estimated breeding values for height and weight will not affect the reproductive performance of Nelore females. Nonetheless, simultaneous selection for growth and reproductive traits is possible.
Assuntos
Bovinos/fisiologia , Reprodução/genética , Escroto/anatomia & histologia , Animais , Teorema de Bayes , Cruzamento , Bovinos/anatomia & histologia , Bovinos/crescimento & desenvolvimento , Feminino , Masculino , DesmameRESUMO
The female reproductive performance, productivity and size are strongly associated with production efficiency of herds raised in a tropical environment. The age at first calving (AFC), accumulated productivity (AP), stayability (STAY) and mature weight (MW) could be used as indicators of these traits. In this study, the genetic parameters and correlations between AFC, AP, STAY and MW measured in Nellore females were estimated, in order to provide support for the beef cattle evaluation programs. In addition, the genetic changes for these traits were obtained. The (co)variance components were estimated by Gibbs sampling by four-trait multivariate analysis, using a threshold animal model for STAY and linear animal model for the other traits (AFC, AP and MW). Heritability of AFC, AP and STAY showed low values, with posterior means of 0.13 ± 0.02, 0.14 ± 0.01 and 0.19 ± 0.03, respectively. On the other hand, for MW were estimated mean heritability of 0.44 ± 0.03 and repeatability of 0.77 ± 0.03, demonstrating the importance of genetic and permanent environmental effects for the expression of beef cows' size. The AFC showed null genetic correlation with AP (-0.06 ± 0.12) and MW (0.01 ± 0.09) and low and negative with STAY (-0.15 ± 0.11). The AP showed high genetic correlation with STAY (0.86 ± 0.03) and weak with MW (0.23 ± 0.09). Positive and moderate genetic association was estimated between STAY and MW (0.66 ± 0.05). Annual direct genetic trends of 0.19 kg, 0.30 units and 0.10 kg were estimated for AP, STAY and MW, respectively, and were significant (P < 0.05) for STAY and MW. For AFC, negative and favorable annual genetic change was estimated (-0.08 months, P < 0.05). In this population, the selection of heifers for an early reproductive age should have little influence, however favorable, in the time that the cows remain in the herd. The use of AP as a selection criterion should result in smaller changes in the females' mature weight when compared to selection based on STAY.
Assuntos
Peso Corporal/genética , Bovinos/genética , Fertilidade/genética , Reprodução/genética , Animais , Feminino , Modelos Genéticos , Característica Quantitativa HerdávelRESUMO
Fertility traits, such as heifer pregnancy, are economically important in cattle production systems, and are therefore, used in genetic selection programs. The aim of this study was to identify single nucleotide polymorphisms (SNPs) using RNA-sequencing (RNA-Seq) data from ovary, uterus, endometrium, pituitary gland, hypothalamus, liver, longissimus dorsi muscle, and adipose tissue in 62 candidate genes associated with heifer puberty in cattle. RNA-Seq reads were assembled to the bovine reference genome (UMD 3.1.1) and analyzed in five cattle breeds; Brangus, Brahman, Nellore, Angus, and Holstein. Two approaches used the Brangus data for SNP discovery 1) pooling all samples, and 2) within each individual sample. These approaches revealed 1157 SNPs. These were compared with those identified in the pooled samples of the other breeds. Overall, 172 SNPs within 13 genes (CPNE5, FAM19A4, FOXN4, KLF1, LOC777593, MGC157266, NEBL, NRXN3, PEPT-1, PPP3CA, SCG5, TSG101, and TSHR) were concordant in the five breeds. Using Ensembl's Variant Effector Predictor, we determined that 12% of SNPs were in exons (71% synonymous, 29% nonsynonymous), 1% were in untranslated regions (UTRs), 86% were in introns, and 1% were in intergenic regions. Since these SNPs were discovered in RNA, the variants were predicted to be within exons or UTRs. Overall, 160 novel transcripts in 42 candidate genes and five novel genes overlapping five candidate genes were observed. In conclusion, 1157 SNPs were identified in 62 candidate genes associated with puberty in Brangus cattle, of which, 172 were concordant in the five cattle breeds. Novel transcripts and genes were also identified.
Assuntos
Puberdade/genética , Animais , Sequência de Bases , Bovinos , Feminino , Fertilidade/genética , Genoma , Masculino , Polimorfismo de Nucleotídeo Único , Gravidez , RNA/genética , Seleção Genética , Análise de Sequência de RNA/métodos , Maturidade SexualRESUMO
The objective of this study was to evaluate associations between single nucleotide polymorphism (SNP) markers and carcass traits measured postmortem in Nellore cattle. Records of loin eye area (LEA) and backfat thickness (BF) from 740 males and records of hot carcass weight (HCW) from 726 males were analyzed. All of the animals were genotyped using the BovineHD BeadChip. Association analyses were performed by the restricted maximum likelihood method that considered one SNP at a time. Significant SNPs were identified on chromosomes 2 and 6 for LEA and on chromosomes 7, 1, and 2 for BF. For HCW, associations with SNPs were found on chromosomes 13, 14, and 28, in addition to genome regions that were directly related to this trait, such as the EFCAB8 and VSTM2L genes, and to bone development (RHOU). Some SNPs were located in very close proximity to genes involved in basal metabolism (BLCAP, NNAT, CTNNBL1, TGM2, and LOC100296770) and the immune system (BPI).
Assuntos
Carne/normas , Animais , Peso Corporal/genética , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Qualidade dos Alimentos , Frequência do Gene , Marcadores Genéticos , Estudo de Associação Genômica Ampla , Genótipo , Masculino , Músculo Esquelético/fisiologia , Polimorfismo de Nucleotídeo Único , Gordura Subcutânea/anatomia & histologiaRESUMO
The objective of this study was to identify associations between known polymorphisms in genes related to adipose tissue and sexual precocity in Nellore cattle. A total of 1689 precocious and non-precocious heifers belonging to farms participating in Conexão Delta G breeding program were studied. SNPs from the Illumina High-Density Bovine SNP BeadChip were used. This chip contains 777,000 SNPs located within the region of the candidate genes at a distance of up to 5 kb, considering that linkage disequilibrium (LD) exists at this distance. Linear models were used for statistical analysis. The fastPHASE and GenomeStudio programs were used for haplotype reconstruction and LD analysis based on r2 statistics. Fifty-seven candidate genes and 443 SNPs were analyzed: among the latter, 370 SNPs formed 83 haplotypes, while the remaining SNPs were studied separately. Statistical analysis showed that only three haplotypes, one haplotype consisting of two SNPs located in the FABP4 gene and two haplotypes consisting of four and two SNPs located in the PPP3CA gene, had a significant effect on sexual precocity at P < 0.05. It can be concluded that the FABP4 and PPP3CA genes influence sexual precocity and may therefore be used in selection programs designed to improve sexual precocity in Nellore cattle.
Assuntos
Bovinos/genética , Estudos de Associação Genética , Metabolismo dos Lipídeos/genética , Puberdade Precoce/genética , Animais , Cromossomos de Mamíferos/genética , DNA/isolamento & purificação , Feminino , Frequência do Gene , Técnicas de Genotipagem , Haplótipos , Masculino , Polimorfismo de Nucleotídeo ÚnicoRESUMO
We analyzed the polymorphisms TFAM HaeIII, TFAM MboI and FABP4 MspA1I in three Nellore lines selected for growth in order to evaluate how selection affects the frequencies of these polymorphisms and evaluate their association with growth and carcass traits in Zebu cattle. Birth, weaning and yearling weights, rump height, longissimus muscle area, backfat thickness, and rump fat thickness were analyzed. The sample was constituted of animals from two lines selected for yearling weight (NeS and NeT), and a control line (NeC), established in 1980, at the São Paulo Instituto de Zootecnia. Two hundred and seventy-two heifers were genotyped for TFAM gene SNPs, and 325 heifers were genotyped for the FABP4 SNP. High frequencies were observed for the alleles A (TFAM HaeIII), C (TFAM MboI) and C (FABP4 MspA1I). Significant differences in allele frequencies between NeS and NeT were observed for the TFAM HaeIII, and between the line NeT and lines NeC and NeS for the FABP4 MspA1I SNP. Five haplotypes were observed for the two polymorphisms in the TFAM gene, haplotype AACC being the most frequent. None of the markers separately or according to haplotype was significantly associated with the growth and carcass traits. The low frequencies of alleles that are associated with high marbling scores and thick subcutaneous fat in taurine breeds might explain the low means for these traits in Nellore cattle.
Assuntos
Bovinos/genética , Proteínas de Ligação a Ácido Graxo/genética , Polimorfismo Genético , Fatores de Transcrição/genética , Animais , Bovinos/crescimento & desenvolvimentoRESUMO
The aim of this study was to analyze LEP and DGAT1 gene polymorphisms in 3 Nelore lines selected for growth and to evaluate their effects on growth and carcass traits. Traits analyzed were birth, weaning, and yearling weight, rump height, LM area, backfat thickness, and rump fat thickness obtained by ultrasound. Two SNP in the LEP gene [LEP 1620(A/G) and LEP 305(T/C)] and the K232A mutation in the DGAT1 gene were analyzed. The sample consisted of 357 Nelore heifers from 2 lines selected for yearling weight and a control line, established in 1980, at the Estação Experimental de Zootecnia de Sertãozinho (Sertãozinho, Brazil). Three genotypes were obtained for each marker. Differences in allele frequencies among the 3 lines were only observed for the DGAT1 K232A polymorphism, with the frequency of the A allele being greater in the control line than in the selected lines. The DGAT1 K232A mutation was associated only with rump height, whereas LEP 1620(A/G) was associated with weaning weight and LEP 305(T/C) with birth weight and backfat thickness. However, more studies, with larger data sets, are necessary before these makers can be used for marker-assisted selection.
Assuntos
Bovinos/genética , Diacilglicerol O-Aciltransferase/genética , Leptina/genética , Polimorfismo de Nucleotídeo Único/genética , Alelos , Animais , Bovinos/crescimento & desenvolvimento , Feminino , Frequência do Gene/genética , Marcadores Genéticos/genética , Genótipo , Masculino , Carne/normas , Músculo Esquelético/crescimento & desenvolvimento , Reação em Cadeia da Polimerase , Locos de Características Quantitativas/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido NucleicoRESUMO
MUC1 is a transmembrane glycoprotein expressed in the male and female reproductive tracts, which plays a broad functional role in reproduction. An important feature ofMUC1 is the presence of a VNTR polymorphism in the extracellular domain that is associated with the function of the molecule. In view of its role in reproduction, the aim of the present study was to analyze the effect of the length of the MUC1 VNTR on the early puberty phenotype in Nelore cattle. A total of 230 heifers were studied, including 77 sexually precocious heifers and 153 regular heifers. The genotype was identified by PCR and the allele and genotype frequencies between the two groups (precocious or regular heifers) were compared by Fishers exact test using the population differentiation module of the GenePop program, version 3.4. The associations between VNTR polymorphism and early puberty were analyzed as discrete data using the SAS GenMod procedure of SAS. Higher frequencies were observed for allele 1, 2, and 3, with allele 1 being predominant in both groups. No significant differences in allele or genotype frequencies were observed between precocious and regular heifers. The analyses using ANOVA and orthogonal contrasts suggest that the MUC1 VNTR variation is not associated with early puberty in cattle. Previous studies regarding the MUC1 polymorphism in Nelore cattle suggested that the high frequency of the 1 allele is a characteristic of Brazilian Nelore cattle.(AU)
Assuntos
Polimorfismo Genético/genética , Puberdade/metabolismo , Fertilidade , Bovinos/classificaçãoRESUMO
MUC1 is a transmembrane glycoprotein expressed in the male and female reproductive tracts, which plays a broad functional role in reproduction. An important feature ofMUC1 is the presence of a VNTR polymorphism in the extracellular domain that is associated with the function of the molecule. In view of its role in reproduction, the aim of the present study was to analyze the effect of the length of the MUC1 VNTR on the early puberty phenotype in Nelore cattle. A total of 230 heifers were studied, including 77 sexually precocious heifers and 153 regular heifers. The genotype was identified by PCR and the allele and genotype frequencies between the two groups (precocious or regular heifers) were compared by Fishers exact test using the population differentiation module of the GenePop program, version 3.4. The associations between VNTR polymorphism and early puberty were analyzed as discrete data using the SAS GenMod procedure of SAS. Higher frequencies were observed for allele 1, 2, and 3, with allele 1 being predominant in both groups. No significant differences in allele or genotype frequencies were observed between precocious and regular heifers. The analyses using ANOVA and orthogonal contrasts suggest that the MUC1 VNTR variation is not associated with early puberty in cattle. Previous studies regarding the MUC1 polymorphism in Nelore cattle suggested that the high frequency of the 1 allele is a characteristic of Brazilian Nelore cattle.
Assuntos
Fertilidade , Polimorfismo Genético/genética , Puberdade/metabolismo , Bovinos/classificaçãoRESUMO
Pregnancy loss can be caused by several factors involved in human reproduction. Although up to 50% of cases remain unexplained, it has been postulated that the major cause of failed pregnancy is an error of embryo implantation. Transmembrane mucin-1 (MUC-1) is a glycoprotein expressed on the endometrial cell surface which acts as a barrier to implantation. The gene that codes for this molecule is composed of a polymorphic tandem repeat of 60 nucleotides. Our objective was to determine if MUC-1 genetic polymorphism is associated with implantation failure in patients with a history of recurrent abortion. The study was conducted on 10 women aged 25 to 35 years with no history of successful pregnancy and with a diagnosis of infertility. The control group consisted of 32 patients aged 25 to 35 years who had delivered at least two full-term live children and who had no history of abortions or fetal losses. MUC-1 amplicons were obtained by PCR and observed on agarose and polyacrylamide gel after electrophoresis. Statistical analysis showed no significant difference in the number of MUC-1 variable number of tandem repeats between these groups (P > 0.05). Our results suggest that there is no effect of the polymorphic MUC-1 sequence on the implantation failure. However, the data do not exclude MUC-1 relevance during embryo implantation. The process is related to several associated factors such as the mechanisms of gene expression in the uterus, specific MUC-1 post-translational modifications and appropriate interactions with other molecules during embryo implantation.
Assuntos
Aborto Habitual/genética , Implantação do Embrião/genética , Infertilidade Feminina/genética , Mucina-1/genética , Polimorfismo Genético , Adulto , Estudos de Casos e Controles , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Reação em Cadeia da Polimerase , GravidezRESUMO
Pregnancy loss can be caused by several factors involved in human reproduction. Although up to 50 percent of cases remain unexplained, it has been postulated that the major cause of failed pregnancy is an error of embryo implantation. Transmembrane mucin-1 (MUC-1) is a glycoprotein expressed on the endometrial cell surface which acts as a barrier to implantation. The gene that codes for this molecule is composed of a polymorphic tandem repeat of 60 nucleotides. Our objective was to determine if MUC-1 genetic polymorphism is associated with implantation failure in patients with a history of recurrent abortion. The study was conducted on 10 women aged 25 to 35 years with no history of successful pregnancy and with a diagnosis of infertility. The control group consisted of 32 patients aged 25 to 35 years who had delivered at least two full-term live children and who had no history of abortions or fetal losses. MUC-1 amplicons were obtained by PCR and observed on agarose and polyacrylamide gel after electrophoresis. Statistical analysis showed no significant difference in the number of MUC-1 variable number of tandem repeats between these groups (P > 0.05). Our results suggest that there is no effect of the polymorphic MUC-1 sequence on the implantation failure. However, the data do not exclude MUC-1 relevance during embryo implantation. The process is related to several associated factors such as the mechanisms of gene expression in the uterus, specific MUC-1 post-translational modifications and appropriate interactions with other molecules during embryo implantation.
Assuntos
Adulto , Feminino , Humanos , Gravidez , Aborto Habitual/genética , /genética , Implantação do Embrião/genética , Infertilidade Feminina/genética , Polimorfismo Genético , Estudos de Casos e Controles , Eletroforese em Gel de Poliacrilamida , Reação em Cadeia da PolimeraseRESUMO
MUC1 is a transmembrane glycoprotein expressed on the apical surfaces of the uterine epithelial tissue with predicted functions in protection and cell-cell adhesion. These properties are closely related with the repetitive region [variable number of tandem repeats (VNTR)] of the extracellullar domain and with the O-glycosylation in their serine and threonine residues. This study describes a polymerase chain reaction (PCR) protocol to analyse MUC1 bovine genetic polymorphism and demonstrates the existence of a VNTR within the sites for O-glycosylation. Oligonucleotide primers based on the Bos taurus mucin (MUC1) gene sequence GenBank AF399757 were used to amplify five VNTR MUC1 alleles from a study group of 56 pure Nelore bovines. The number of repeats varied between 10 and 24, being more prevalent than the alleles with less number of repeats. The DNA sequence analysis revealed two repeats and one of them presented 100% homology with the bovine consensus sequence already reported. The second repeat showed codons that translate to serine and proline amino acids, which are conserved in the MUC1 of several species. This study is the first description of allelic variation and the VNTR structure in the Nelore breed MUC1 gene, and we suggest that this genetic variability can be tested for association with variation in reproductive traits in Nelore cattle.