RESUMO
The gilthead seabream (Sparus aurata, Sparidae family) is commonly used for aquaculture. Despite its great economic value, several problems in its cultivation remain. One of the major concerns is the high frequency of morphological abnormalities occurring during the early developmental stages. Partial and/or total lack of operculum is the most frequent anomaly affecting the fish cranial region. The existence of genetic factors that can at least partially determine this defect has been hypothesized. In this work, two DNA pools of highly related fry, one composed of normal-looking (control) fish and the other lacking an operculum (case), were constructed and whole-genome resequencing data produced from the two were compared. The analysis revealed a 1 Mb region on chromosome 2 with higher heterozygosity in the lack of operculum DNA pool than in the control DNA pool, consistent with the enrichment, in the first DNA pool, of one or more haplotypes causing or predisposing to the defect together with other normal haplotypes. A window-based FST analysis between the two DNA pools indicated that the same region had the highest divergence score. This region contained 2921 SNVs, 10 of which, with predicted high impacts (three splice donor and seven stop-gained variants), were detected in novel genes that are homologous to calcium-sensing receptor-like genes, probably involved in bone development. Other studies are needed to clarify the genetic mechanisms involved in predisposing fry to this deformity and then to identify associated markers that could be used in breeding programs to reduce the frequency of this defect in the broodstock.
Assuntos
Osso e Ossos/anormalidades , Doenças dos Peixes/genética , Dourada/genética , Animais , Aquicultura , Feminino , Haplótipos , Masculino , Polimorfismo de Nucleotídeo Único , Dourada/anormalidades , Sequenciamento Completo do Genoma/veterináriaRESUMO
In the European rabbit (Oryctolagus cuniculus), a polytocous livestock species, the number of teats indirectly impacts the doe reproduction efficiency and, in turn, the sustainable production of rabbit meat. In this study, we carried out a genome-wide association study (GWAS) for the total number of teats in 247 Italian White does included in the Italian White rabbit breed selection program, by applying a selective genotyping approach. Does had either 8 (n = 121) or 10 teats (n = 126). All rabbits were genotyped with the Affymetrix Axiom OrcunSNP Array. Genomic data from the two extreme groups of rabbits were also analysed with the single-marker fixation index statistic and combined with the GWAS results. The GWAS identified 50 significant SNPs and the fixation index analysis identified a total of 20 SNPs that trespassed the 99.98th percentile threshold, 19 of which confirmed the GWAS results. The most significant SNP (P = 4.31 × 10-11 ) was located on OCU1, close to the NUDT2 gene, a breast carcinoma cells proliferation promoter. Another significant SNP identified as candidate gene NR6A1, which is well known to play an important role in affecting the correlated number of vertebrae in pigs. Other significant markers were close to candidate genes involved in determining body length in mice. Markers associated with increased number of teats could be included in selection programmes to speed up the improvement for this trait in rabbit lines that need to increase maternal performances.
Assuntos
Glândulas Mamárias Animais/anatomia & histologia , Coelhos/genética , Animais , Cruzamento , Feminino , Estudos de Associação Genética/veterinária , Marcadores Genéticos , Técnicas de Genotipagem/veterinária , Fenótipo , Polimorfismo de Nucleotídeo Único , Coelhos/anatomia & histologiaRESUMO
The gilthead seabream (Sparus aurata) is an important cultivated species in the Mediterranean area. A major problem for the gilthead seabream aquaculture sector derives from the high frequency of phenotypic abnormalities, including discolorations. In this study, we applied a whole-genome resequencing approach to identify a genomic region affecting a pigmentation defect that occurred in a cultivated S. aurata population. Two equimolar DNA pools were constructed using DNA extracted from 30 normally coloured and 21 non-pigmented fish collected among the offspring of the same broodstock nucleus. Whole-genome resequencing reads from the two DNA pools were aligned to the S. aurata draft genome and variant calling was performed. A whole-genome heterozygosity scan from single pool sequencing data highlighted a peak of reduced heterozygosity of approximately 5 Mbp on chromosome 6 in the non-pigmented pool that was not present in the normally coloured pool. The comparison of the non-pigmented with the normally coloured fish using a whole-genome FST analysis detected three main regions within the coordinates previously detected with the heterozygosity analysis. The results support the presence of a major locus affecting this discoloration defect in this fish population. The results of this study have practical applications, including the possibility of eliminating this defect from the breeding stock, with direct economic advantages derived from the reduction of discarded fry. Other studies are needed to identify the candidate gene and the causative mutation, which could add information to understand the complex biology of fish pigmentation.
Assuntos
Pigmentação/genética , Dourada/fisiologia , Sequenciamento Completo do Genoma/veterinária , Animais , Aquicultura , Dourada/genéticaRESUMO
Intermuscular fat content in protected designations of origin dry-cured hams is a very important meat quality trait that affects the acceptability of the product by the consumers. An excess in intermuscular fat (defined as the level of fat deposition between leg muscles) is a defect that depreciates the final product. In this study we carried out a genome-wide association study for visible intermuscular fat (VIF) of hams in the Italian Large White pig breed. This trait was evaluated on the exposed muscles of green legs in 1122 performance-tested gilts by trained personnel, according to a classification scale useful for routine and cheap evaluation. All animals were genotyped with the Illumina PorcineSNP60 BeadChip. The genome-wide association study identified three QTL regions on porcine chromosome 1 (SSC1; accounting for ~79% of the SNPs below the 5.0E-04 threshold) and SSC2, two on SSC7 and one each on SSC3, SSC6, SSC9, SSC11, SSC13, SSC15, SSC16 and SSC17. The most significant SNP (ALGA0004143 on SSC1 at 77.3 Mb; PFDR < 0.05), included in the largest QTL region which spanned about 6.8 Mb on SSC1, is located within the glutamate ionotropic receptor kainate type subunit 2 (GRIK2) gene. Functional annotation of all genes included in QTL regions for VIF suggested that intermuscular fat in the Italian Large White breed is a complex trait apparently influenced by complex biological mechanisms also involving obesity-related processes. These QTL target mainly chromosome regions different from those affecting subcutaneous and intramuscular fat deposition.
Assuntos
Adiposidade/genética , Locos de Características Quantitativas , Carne Vermelha , Sus scrofa/genética , Tecido Adiposo , Animais , Cruzamento , Feminino , Estudos de Associação Genética , Genótipo , Itália , Modelos Lineares , Masculino , Modelos Genéticos , Músculo Esquelético , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Protected designation of origin dry-cured hams are the most important productions of the Italian heavy pig industry. Hams capable of minimal seasoning losses produce better quality dry-cured hams. Ham weight loss during the first 7 days in brine (first salting) is highly correlated with the total loss of weight up to the end of seasoning, and it has quite high heritability (0.30-0.61). For these reasons, ham weight loss at first salting has been included as a meat quality trait in the Italian heavy pig selection program. In this work, we carried out a genome-wide association study for this parameter in the Italian Large White pig breed by genotyping 1365 animals with the Illumina BeadChip PorcineSNP60 chip. A total of 44 single nucleotide polymorphisms (SNPs) had a Pnominal value below 5.0E-04, five of which were below 5.0E-05 and one of them (ALGA0057985 on chromosome 10) was associated with this trait at a PBonferroni threshold of 0.10. These SNPs identified a total of at least 29 putative QTLs that were located on most porcine autosomal chromosomes. This study provides genomic information that could be useful in dissecting this complex trait by identifying potential candidate genes whose function could contribute to understanding the biological mechanisms affecting meat quality for seasoning aptitude.
Assuntos
Manipulação de Alimentos , Polimorfismo de Nucleotídeo Único , Carne Vermelha/análise , Sus scrofa/genética , Animais , Cruzamento , Feminino , Estudos de Associação Genética , Genótipo , Masculino , Fenótipo , Locos de Características Quantitativas , Cloreto de Sódio na DietaRESUMO
In this study, we investigated at the genome-wide level if 20 years of artificial directional selection based on boar genetic evaluation obtained with a classical BLUP animal model shaped the genome of the Italian Large White pig breed. The most influential boars of this breed (n = 192), born from 1992 (the beginning of the selection program of this breed) to 2012, with an estimated breeding value reliability of >0.85, were genotyped with the Illumina Porcine SNP60 BeadChip. After grouping the boars in eight classes according to their year of birth, filtered single nucleotide polymorphisms (SNPs) were used to evaluate the effects of time on genotype frequency changes using multinomial logistic regression models. Of these markers, 493 had a PBonferroni < 0.10. However, there was an increasing number of SNPs with a decreasing level of allele frequency changes over time, representing a continuous profile across the genome. The largest proportion of the 493 SNPs was on porcine chromosome (SSC) 7, SSC2, SSC8 and SSC18 for a total of 204 haploblocks. Functional annotations of genomic regions, including the 493 shifted SNPs, reported a few Gene Ontology terms that might underly the biological processes that contributed to increase performances of the pigs over the 20 years of the selection program. The obtained results indicated that the genome of the Italian Large White pigs was shaped by a directional selection program derived by the application of methodologies assuming the infinitesimal model that captured a continuous trend of allele frequency changes in the boar population.
Assuntos
Cruzamento , Frequência do Gene , Seleção Genética , Suínos/genética , Animais , Genoma , Genótipo , Modelos Logísticos , Masculino , Modelos Genéticos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Calcium, magnesium and phosphorus are essential electrolytes involved in a large number of biological processes. Imbalance of these minerals in blood may indicate clinically relevant conditions and are important in inferring acute or chronic pathologies in humans and animals. In this work, we carried out a genome-wide association study (GWAS) for the level of these three electrolytes in the serum of 843 performance-tested Italian Large White pigs. All pigs were genotyped with the Illumina PorcineSNP60 BeadChip, and GWAS was carried out using genome-wide efficient mixed-model association. For the level of Ca(2+) , eight single nucleotide polymorphisms (SNPs) were significant, considering a false discovery rate (FDR) < 0.05, and another eight were above the moderate association threshold (Pnominal value < 5.00E-05). These SNPs are distributed in four porcine chromosomes (SSC): SSC8, SSC11, SSC12 and SSC13. In particular, a few putative different signals of association detected on SSC13 and one on SSC12 were in genes or close to genes involved in calcium metabolism (P2RY1, RAP2B, SLC9A9, C3orf58, TSC22D2, PLCH1 and CACNB1). Only one SNP (on SSC7) and six SNPs (on SSC2 and SSC7) showed moderate association with the level of magnesium and phosphorus respectively. The association signals for these two latter minerals might identify genes not known thus far for playing a role in their biological functions and regulations. In conclusion, our GWAS contributed to increased knowledge on the role that calcium, magnesium and phosphorus may play in the genetically determined physiological mechanisms affecting the natural variability of mineral levels in mammalian blood.
Assuntos
Eletrólitos/sangue , Estudos de Associação Genética , Polimorfismo de Nucleotídeo Único , Sus scrofa/genética , Animais , Cálcio/sangue , Feminino , Genótipo , Magnésio/sangue , Masculino , Modelos Genéticos , Fósforo/sangueRESUMO
In this study, we investigated whether a selection programme based on boar genetic evaluation obtained with a classical BLUP animal model can change allele frequencies in a pig population. All Italian Large White boars born from 1992 to 2012 with estimated breeding value reliability >0.85 (n = 200) were selected among all boars of this breed. Boars were genotyped with markers in major genes (IGF2 intron3-g.3072G>A, MC4R p.D298N, VRTN PRE1 insertion, PRKAG3 p.I199V and FTO g.276T>G). Genotyping data were analysed grouping boars in eight classes according to their year of birth. To evaluate the influence of time on allele frequencies of the genotyped markers, multinomial logistic regression models were computed. Four of five polymorphic sites (IGF2, MC4R, VRTN and FTO) showed significant (p < 0.01) changes in allele frequencies over time due to a progressive and continuous increase of one allele (associated with higher lean meat content, higher average daily gain and favourable feed: gain ratio) and, consequently, decrease of the other one, following the directional selection of the selection programme of this pig breed. The retrospective analysis that was carried out in Italian Large White boars suggests that selection based on methodologies assuming the infinitesimal model is able to modify in a quite short period of time allele frequencies in major genes, increasing the frequency of alleles explaining a relevant (non-infinitesimal) fraction of the overall genetic variability for production traits.
Assuntos
Frequência do Gene , Suínos/genética , Animais , Cruzamento , Feminino , Marcadores Genéticos/genética , Masculino , Estudos RetrospectivosRESUMO
The widespread use of genome-wide association studies resulted in the discovery of genomic regions associated with fatty acid (FA) composition in different porcine tissues, but little information exists about the genes involved in FA composition of meat obtained from heavy pigs selected for the production of Italian dry-cured hams. To this objective, we genotyped with a single nucleotide polymorphism (SNP) panel 795 Italian Large White heavy pigs to identify the markers and genomic regions associated with Semimembranosus muscle FA profile. Heritability estimates for intramuscular fat FA profile were of low-to-moderate magnitude, suggesting that these traits may be improved with genomic selection. On the whole, 45 SNPs were significantly associated with 14 FAs, and 4 of them (ALGA008109, ALGA0081097, CASI0010164 and SIRI0000267) were associated with more than 1 FA. The palmitoleic : palmitic and oleic : stearic ratios displayed the highest number of significant markers and the most significant associations (Bonferroni adjusted P < 5.00E-07). Of particular interest, the palmitoleic : palmitic ratio was strongly associated with markers located at 111 to 114 Mb on chromosome 14, in the same chromosomal region where Stearoyl-CoA desaturase Δ9 (SCD) gene is located. Several significant chromosomal regions were found; some of them harbour key genes playing pivotal roles in FA desaturation and elongation, such as SCD and some members of the Elongation of Very Long-Chain FA (ELOVL) gene family. The results suggest that the identification of causal mutations in these regions may provide a set of markers useful for selection schemes aimed at improving FA composition in pork products.
Assuntos
Estudo de Associação Genômica Ampla , Locos de Características Quantitativas , Suínos , Animais , Ácidos Graxos , Estudo de Associação Genômica Ampla/veterinária , Genótipo , Itália , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Suínos/genéticaRESUMO
In humans, common variants in the fat mass and obesity associated (FTO) gene are associated with body mass index and obesity. Here we sequenced exon 4, parts of introns 3 and 4 and two portions of the 3'-untranslated region of the porcine FTO gene in a panel of nine pigs of different breeds and identified three SNPs. Allele frequencies of the g.276T>G (AM931150) mutation were studied in seven pig breeds. This mutation was used to linkage-map FTO to SSC6. Association analyses between the g.276T>G polymorphism and several traits [pH of semimembranosus muscle and estimated breeding values (EBV) for average daily gain, back fat thickness, lean cuts, ham weight and feed:gain ratio] were carried out in 257 sib-tested Italian Large White pigs. Only feed:gain ratio showed P<0.05. A selective genotyping approach was applied, analysing two extreme and divergent groups of Italian Large White pigs selected on the basis of back fat thickness EBV (50 with most positive and 50 with most negative values). Fisher's exact test (two-tailed) was not significant when comparing the allele frequencies of these two groups. The same approach was used in the Italian Duroc breed for which two extreme and divergent groups of animals were selected according to visible intermuscular fat EBV. Differences of allele frequencies between these two groups were highly significant (P<0.00001, P<0.001 and P<0.0001, considering all animals or only two- or three-generation unrelated animals respectively), indicating association between the analysed FTO marker and intermuscular fat deposition.
Assuntos
Índice de Massa Corporal , Obesidade , Proteínas/genética , Sus scrofa/genética , AnimaisRESUMO
Longevity is one of the most important traits determining dairy cow profitability. In the last decades dairy cows suffered a lowering in the age at culling. With the aim to identify the genes involved in longevity, dates of birth, yields, dates of calving during lifespan and culling dates were collected for 946 culled cows which had been genotyped with the Bovine High Density panel. Using the GenABEL package in R, genome-wide association analysis was performed on three potential traits of longevity: (1) 'days in production,' (2) 'days in herd,' (3) number of calvings over lifespan.' Five genome-wide significant single nucleotide polymorphisms (SNPs) associated with all three longevity traits were detected. Several consecutive SNPs identified on chromosomes 16 and 30 indicated the presence of two suggestive quantitative trait loci (QTL). The genes comprised in the QTL regions had biological functions related to fertility, reproductive disorders, heat stress and welfare of cows. These findings might contribute to improving breeding strategies to improve longevity.
Assuntos
Bovinos/genética , Bovinos/fisiologia , Estudo de Associação Genômica Ampla/veterinária , Longevidade/genética , Animais , Feminino , Genótipo , Polimorfismo de Nucleotídeo Único , Gravidez , Locos de Características QuantitativasRESUMO
Subcutaneous fat thickness and fatty acid composition (FAC) play an important role on seasoning loss and organoleptic characteristics of seasoned hams. Dry-cured ham industry prefers meats with low contents of polyunsaturated fatty acids (PUFA) because these negatively affect fat firmness and ham quality, whereas consumers require higher contents in those fatty acids (FA) for their positive effect on human health. A population of 950 Italian Large White pigs from the Italian National Sib Test Selection Programme was investigated with the aim to estimate heritabilities, genetic and phenotypic correlations of backfat FAC, Semimembranosus muscle intramuscular fat (IMF) content and other carcass traits. The pigs were reared in controlled environmental condition at the same central testing station and were slaughtered at reaching 150 kg live weight. Backfat samples were collected to analyze FAC by gas chromatography. Carcass traits showed heritability levels from 0.087 for estimated carcass lean percentage to 0.361 for hot carcass weight. Heritability values of FA classes were low-to-moderate, all in the range 0.245 for n-3 PUFA to 0.264 for monounsaturated FA (MUFA). Polyunsaturated fatty acids showed a significant genetic correlation with loin thickness (0.128), backfat thickness (-0.124 for backfat measured by Fat-O-Meat'er and -0.175 for backfat measured by calibre) and IMF (-0.102). Obviously, C18:2(n-6) shows similar genetic correlations with the same traits (0.211 with loin thickness, -0.206 with backfat measured by Fat-O-Meat'er, -0.291 with backfat measured by calibre and -0.171 with IMF). Monounsaturated FA, except with the backfat measured by calibre (0.068; P<0.01), do not show genetic correlations with carcass characteristics, whereas a negative genetic correlation was found between MUFA and saturated FA (SFA; -0.339; P<0.001). These results suggest that MUFA/SFA ratio could be increased without interfering with carcass traits. The level of genetic correlations between FA and carcass traits should be taken into account in dealing with the development of selection schemes addressed to modify carcass composition and/or backfat FAC.
Assuntos
Ácidos Graxos/metabolismo , Carne/análise , Músculo Esquelético/metabolismo , Gordura Subcutânea/metabolismo , Sus scrofa/fisiologia , Animais , Feminino , Genótipo , Masculino , Fenótipo , Sus scrofa/genéticaRESUMO
The objective of this study was to investigate the association of DNA markers in candidate genes for glycolytic potential on meat quality parameters (pH(1), pH(u), glycogen and lactate content and glycolytic potential of semimembranosus muscle) and estimated breeding values (EBVs) for average daily gain, lean cuts, back fat thickness, ham weight, and feed:gain ratio in 272 Italian Large White pigs. Three mutations in the PRKAG3 gene (T30N, G52S and I199V) were investigated as well as single nucleotide polymorphisms in two other skeletal muscle genes (PGAM2 and PKM2) involved in the glycolytic pathway. Association analysis with the PRKAG3 markers showed significant results (P<0.05) only for pH(1) (I199V, with significant additive effect) and lactate content (T30N), confirming, at least in part, the effects of this gene on meat quality traits. Significant association (P<0.05) was also observed for PGAM2 and ham weight EBV with significant additive and dominance effects. PKM2 was associated with average daily gain, lean cuts (P<0.001), back fat thickness and feed:gain ratio (P<0.05), with significant additive and/or dominance effects on these traits. PKM2 encodes for a key enzyme of the muscle glycolytic pathway and maps on porcine chromosome 7 where other studies have reported important QTL for the same traits. These data might suggest an important function of this gene in the mechanisms that produce the observed effects. The results will be important to evaluate the inclusion of some of these DNA polymorphisms in marker assisted selection programs.
RESUMO
Protected designation of origin dry-cured hams are obtained from heavy pigs (slaughtered at about 160 kg of live weight). A specific breeding program designed to improve meat quality for this production has included as key traits the level of intermuscular fat between the leg muscles and ham weight loss during the seasoning period together with a balance between fat and lean cuts. In this study we carried out genome-wide association studies for seven traits used in the genetic merit of Italian Duroc heavy pigs, five related to meat and carcass quality traits (visible intermuscular fat, ham weight loss at first salting, backfat thickness, ham weight and lean cuts), and two related to performance and efficiency traits (average daily gain and feed : gain ratio). A total of 573 performance-tested pigs were genotyped with the Illumina PorcineSNP60 BeadChip and genome-wide association analyses were carried out using the Bayes B approach with the 1 Mb window option of GenSel and random residuals for each of the seven traits. Detected windows were supported by independent single nucleotide polymorphism analyses with a linear mixed model (LMM) approach on the same animals for the same traits. A total of 30 windows identifying different quantitative trait loci (QTL) were detected and among those, 27 were confirmed by LMM in one of these traits. Among the confirmed windows, three QTL were reported for visible intermuscular fat, seven for ham weight loss at first salting and five and four for backfat thickness and lean cut, respectively. A total of eight QTL were detected for the other production traits. No overlapping QTL were reported except for one window on porcine chromosome 10 between lean cuts and ham weight that contained the CACNB2 gene that has been already associated with loin marbling score in other Duroc pigs. Several regions contained genes that have been already associated with production traits in other pig breeds, including Duroc lines, related to fat deposition or muscle structure. This work reports, for the first time, genome-wide association study results for several traits in Italian Duroc heavy pigs. These results will be useful to dissect the genetic basis for dry-cured ham production traits that determine the total genetic merit index of Italian Duroc pigs.
Assuntos
Estudo de Associação Genômica Ampla , Carne , Suínos , Animais , Teorema de Bayes , Genômica , Itália , Polimorfismo de Nucleotídeo Único , Suínos/genética , Suínos/crescimento & desenvolvimentoAssuntos
L-Lactato Desidrogenase/genética , Carne/normas , Suínos/crescimento & desenvolvimento , Suínos/genética , Animais , Feminino , Estudos de Associação Genética , Isoenzimas/genética , Lactato Desidrogenase 5 , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Aumento de PesoRESUMO
This study seeks to verify the feasibility of increasing twinning in a herd of the Italian autochtonous Maremmana breed. The data set included 1260 individuals born from 1963 to 2014, 527 males and 733 females, 402 of them calving at least once from 1983 through 2015. Breeding values for twinning were estimated by a single-trait linear animal model. However, since twinning is a dichotomous trait and the frequency of twins is far smaller than the frequency of single births, breeding values were also estimated by a single-trait animal threshold model. Heritability of twinning was 0.014±0.018 and 0.062±0.093 for the linear and the threshold models, respectively. Repeatability was 0.071±0.004 and 0.286± 0.012, respectively, for the two models. Genotyping with the Illumina BovineSNP54 BeadChip was performed for cows living on farm in 2012 (119 cows) and a genome-wide association analysis was performed on the corrected phenotype of all calving during the lifespan of each cow, using the GenABEL package in R and a three step GRAMMAR-GC approach. Genomic heritability, calculated from the genomic kinship matrix estimated through genomic marker data, was 0.29±0.021. The most significant detected single nucleotide polymorphisms (Hapmap22923-BTA-129564) was located in proximity of two genes, ARHGAP8 and TMEM200C, which might be potential functional candidates for twinning rate in cattle.
Assuntos
Bovinos/genética , Estudo de Associação Genômica Ampla , Animais , Cruzamento , Bovinos/fisiologia , Feminino , Genótipo , Modelos Lineares , Tamanho da Ninhada de Vivíparos/genética , Masculino , FenótipoRESUMO
Genomic selection is becoming a common practise in dairy cattle, but only few works have studied its introduction in pig selection programs. Results described for this species are highly dependent on the considered traits and the specific population structure. This paper aims to simulate the impact of genomic selection in a pig population with a training cohort of performance-tested and slaughtered full sibs. This population is selected for performance, carcass and meat quality traits by full-sib testing of boars. Data were simulated using a forward-in-time simulation process that modeled around 60K single nucleotide polymorphisms and several quantitative trait loci distributed across the 18 porcine autosomes. Data were edited to obtain, for each cycle, 200 sires mated with 800 dams to produce 800 litters of 4 piglets each, two males and two females (needed for the sib test), for a total of 3200 newborns. At each cycle, a subset of 200 litters were sib tested, and 60 boars and 160 sows were selected to replace the same number of culled male and female parents. Simulated selection of boars based on performance test data of their full sibs (one castrated brother and two sisters per boar in 200 litters) lasted for 15 cycles. Genotyping and phenotyping of the three tested sibs (training population) and genotyping of the candidate boars (prediction population) were assumed. Breeding values were calculated for traits with two heritability levels (h 2=0.40, carcass traits, and h 2=0.10, meat quality parameters) on simulated pedigrees, phenotypes and genotypes. Genomic breeding values, estimated by various models (GBLUP from raw phenotype or using breeding values and single-step models), were compared with the classical BLUP Animal Model predictions in terms of predictive ability. Results obtained for traits with moderate heritability (h 2=0.40), similar to the heritability of traits commonly measured within a sib-testing program, did not show any benefit from the introduction of genomic selection. None of the considered genomic models provided improvements in prediction ability of pigs with no recorded phenotype. However, a few advantages were found for traits with low heritability (h 2=0.10). These heritability levels are characteristic for meat quality traits recorded after slaughtering or for reproduction or health traits, typically recorded on field and not in performance stations. Other scenarios of data recording and genotyping should be evaluated before considering the implementation of genomic selection in a pig-selection scheme based on sib testing of boars.
Assuntos
Genômica/métodos , Suínos/genética , Animais , Cruzamento , Feminino , Genótipo , Masculino , Modelos Genéticos , Linhagem , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Seleção GenéticaRESUMO
Genes coding for sarcomeric proteins may play a key role in muscle mass accretion and meat production. Screening a skeletal muscle cDNA library we isolated two partial sequences coding for the sarcomeric myopalladin and titin genes. In the present work we identified three SNPs in the 3' untranslated region, two at the myopalladin locus and one at the titin locus. Myopalladin was mapped on porcine chromosome (SSC) 14 using a somatic cell hybrid panel, a radiation hybrid panel and by linkage mapping. The linkage mapping of titin confirmed the position on SSC15. Then we analysed the allelic distribution of the alleles at both loci in six different porcine breeds. The analysis of the allele frequencies for these two loci in extremely divergent groups of pigs selected according to lean cuts (LC) and average daily gain (ADG) approached the significance level for myopalladin and LC trait. Further studies are needed to test the presence of a putative effect of myopalladin on lean meat content.
Assuntos
Mapeamento Cromossômico/veterinária , Frequência do Gene/genética , Proteínas Musculares/genética , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Polimorfismo Genético/genética , Proteínas Quinases/genética , Suínos/genética , Animais , Cruzamento , Mapeamento Cromossômico/métodos , Conectina , Ligação Genética/genética , Células Híbridas , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , Mapeamento de Híbridos Radioativos/métodos , Mapeamento de Híbridos Radioativos/veterinária , Especificidade da EspécieRESUMO
The authors discuss the meaning of the "innominate grooves" of the colon after having determined their anatomic substratum with a microradiographic study. In the iconographic and methodological critical evaluation of the double contrast technique the "innominate grooves" must be considered as an important sign of today's radiologic semeiotics and as elementary mucous structures which are first affected by pathologic situations.
Assuntos
Colo/patologia , Mucosa Intestinal/diagnóstico por imagem , Óleo de Rícino/uso terapêutico , Catárticos/uso terapêutico , Colo/diagnóstico por imagem , Enema , Humanos , Radiografia , Tecnologia RadiológicaRESUMO
A case of oro-pharyngeal oesophagus papillomatosis is described. It was associated with an adeno-carcinoma of the stomach. A brief, critical review of the literature with consideration of the aetiology and pathology is given.