Search tips
Search criteria

Results 1-6 (6)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
1.  Deep Intronic Mutation and Pseudo Exon Activation as a Novel Muscular Hypertrophy Modifier in Cattle 
PLoS ONE  2014;9(5):e97399.
Myostatin is essential for proper regulation of myogenesis, and inactivation of Myostatin results in muscle hypertrophy. Here, we identified an unexpected mutation in the myostatin gene which is almost fixed in Blonde d'Aquitaine cattle. In skeletal muscle, the mutant allele was highly expressed leading to an abnormal transcript consisting of a 41-bp inclusion and premature termination codons and to residual levels of a correctly spliced transcript. This expression pattern, caused by a leaky intronic mutation with regard to spliceosome activity and its apparent stability with regard to surveillance mechanisms, could contribute to the moderate muscle hypertrophy in this cattle breed. This finding is of importance for genetic counseling for meat quantity and quality in livestock production and possibly to manipulate myostatin pre-mRNA in human muscle diseases.
PMCID: PMC4020855  PMID: 24827585
2.  The GENOTEND chip: a new tool to analyse gene expression in muscles of beef cattle for beef quality prediction 
Previous research programmes have described muscle biochemical traits and gene expression levels associated with beef tenderness. One of our results concerning the DNAJA1 gene (an Hsp40) was patented. This study aims to confirm the relationships previously identified between two gene families (heat shock proteins and energy metabolism) and beef quality.
We developed an Agilent chip with specific probes for bovine muscular genes. More than 3000 genes involved in muscle biology or meat quality were selected from genetic, proteomic or transcriptomic studies, or from scientific publications. As far as possible, several probes were used for each gene (e.g. 17 probes for DNAJA1). RNA from Longissimus thoracis muscle samples was hybridised on the chips. Muscles samples were from four groups of Charolais cattle: two groups of young bulls and two groups of steers slaughtered in two different years. Principal component analysis, simple correlation of gene expression levels with tenderness scores, and then multiple regression analysis provided the means to detect the genes within two families (heat shock proteins and energy metabolism) which were the most associated with beef tenderness. For the 25 Charolais young bulls slaughtered in year 1, expression levels of DNAJA1 and other genes of the HSP family were related to the initial or overall beef tenderness. Similarly, expression levels of genes involved in fat or energy metabolism were related with the initial or overall beef tenderness but in the year 1 and year 2 groups of young bulls only. Generally, the genes individually correlated with tenderness are not consistent across genders and years indicating the strong influence of rearing conditions on muscle characteristics related to beef quality. However, a group of HSP genes, which explained about 40% of the variability in tenderness in the group of 25 young bulls slaughtered in year 1 (considered as the reference group), was validated in the groups of 30 Charolais young bulls slaughtered in year 2, and in the 21 Charolais steers slaughtered in year 1, but not in the group of 19 steers slaughtered in year 2 which differ from the reference group by two factors (gender and year). When the first three groups of animals were analysed together, this subset of genes explained a 4-fold higher proportion of the variability in tenderness than muscle biochemical traits.
This study underlined the relevance of the GENOTEND chip to identify markers of beef quality, mainly by confirming previous results and by detecting other genes of the heat shock family as potential markers of beef quality. However, it was not always possible to extrapolate the relevance of these markers to all animal groups which differ by several factors (such as gender or environmental conditions of production) from the initial population of reference in which these markers were identified.
PMCID: PMC3438070  PMID: 22894653
Predictors; Beef; Tenderness; Array; Gene expression
3.  Genetic relationship between cyclic ovarian activity in heifers and cows and beef traits in males 
Records were collected in an experimental herd over an 11-year period from purebred Charolais heifers (n = 351), cows (n = 615) and young entire bulls (n = 383). The objective of the study was to estimate the genetic relationship between the components of female ovarian activity (age at puberty and postpartum anoestrus length), their growth rate and body condition score and beef traits measured on related bulls. Two methods were used to estimate age at puberty and postpartum anoestrus length: the detection of oestrous behaviour and a test of cyclicity based on plasmatic progesterone assay. This study shows the existence of significant heritability estimates for the different cyclicity traits (h2 between 0.11 and 0.38). Most of the genetic correlation coefficients between ovarian activity and growth rate of females and males are negative and favourable (rg between -0.43 and 0.06). Cyclicity is also favourably related with body condition score in young or adult females (rg between -0.65 and -0.22). The genetic relationship between female ovarian activity and proportion of adipose tissue in the male carcass is, however, close to zero. These results show that an antagonism between male beef traits measured in this study and female ovarian activity is unlikely to be a cause for concern in the short term.
PMCID: PMC2705408  PMID: 11403748
genetic relationships; ovarian activity; beef-traits; cattle
4.  Genetic correlation estimations between artificial insemination sire performances and their progeny beef traits both measured in test stations 
In France, beef traits of artificial insemination (AI) beef bulls are improved through the sequential selection for their own performances and for their male progeny performances, both being recorded in test stations. The efficiency of such programmes mainly depends on the genetic correlations between sire performances and progeny beef traits. Such correlations were independently estimated, using the multivariate REML (restricted maximum likelihood) method in a Limousin and a Charolais programme. In both breeds, high genetic correlations were observed between sires and progeny analogous morphology scores (from 0.64 to 0.82). Genetic correlations estimated between sires and progeny growth (from 0.41 to 0.70) were lower probably due to the difference of diet in central and progeny stations. Correlations between sire muscling scores and progeny skeletal frames (and vice-versa) were negative (from -0.05 to -0.58). The genetic correlations of sire traits with progeny dressing percentage (DPp) and carcass fatness score (CFp) were only low to moderate. These results show that the selection of bulls at the end of performance testing in test stations may be efficient in improving progeny growth and morphology. However, such a selection is insufficient in improving their dressing percentage and carcass composition.
PMCID: PMC2706873  PMID: 14736377
genetic correlation; live and carcass traits;  Charolais and Limousin breeds; selection efficiency
5.  Genetic variability of the length of postpartum anoestrus in Charolais cows and its relationship with age at puberty 
Fertility records (n = 1 802) were collected from 615 Charolais primiparous and multiparous cows managed in an experimental herd over an 11-year period. The objectives of the study were to describe the genetic variability of the re-establishment of postpartum reproductive activity and the relationship with body weight (BW) and body condition score (BCS) at calving and age at puberty. The length of postpartum anoestrus was estimated based on weekly blood progesterone assays and on twice daily detection of oestrus behaviour. The first oestrus behaviour was observed 69 days (± 25 days s.d.) post-calving and the first positive progesterone measurement (≥ 1 ng mL-1) was observed at 66 days (± 22 days s.d.) for the group of easy-calving multiparous suckling cows. Estimates of heritability and repeatability were h2 = 0.12 and r = 0.38 respectively, for the interval from calving to first oestrus (ICO). Corresponding values were h2 = 0.35 and r = 0.60 for the interval from calving to the first positive progesterone test (ICP). The genetic correlation between both criteria was high (rg = 0.98). The genetic relationships between postpartum intervals and BW and BCS of the female at calving were negative: the genetic aptitude to be heavier at calving and to have high body reserves was related to shorter postpartum intervals. A favourable genetic correlation between age at puberty and postpartum intervals was found (rg between 0.45 and 0.70). The heifers which were genetically younger at puberty also had shorter postpartum intervals.
PMCID: PMC2706853  PMID: 14736386
beef cattle; postpartum; puberty; body weight; genetic parameter

Results 1-6 (6)