R. Finocchiaro

Missense and nonsense mutations in melanocortin 1 receptor (MC1R) gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences

BackgroundAgouti and Extension loci control the relative amount of eumelanin and pheomelanin production in melanocytes that, in turn, affects pigmentation of skin and hair. The Extension locus encodes the melanocortin 1 receptor (MC1R) whose permanent activation, caused by functional mutations, results in black coat colour, whereas other inactivating mutations cause red coat colour in different mammals.ResultsThe whole coding region of the MC1R gene was sequenced in goats of six different breeds showing different coat colours (Girgentana, white cream with usually small red spots in the face; Maltese, white with black cheeks and ears; Derivata di Siria, solid red; Murciano-Granadina, solid black or solid brown; Camosciata delle Alpi, brown with black stripes; Saanen, white; F1 goats and the parental animals). Five single nucleotide polymorphisms (SNPs) were identified: one nonsense mutation (p.Q225X), three missense mutations (p.A81V, p.F250V, and p.C267W), and one silent mutation. The stop codon at position 225 should cause the production of a shorter MC1R protein whose functionality may be altered. These SNPs were investigated in a larger sample of animals belonging to the six breeds. The Girgentana breed was almost fixed for the p.225X allele. However, there was not complete association between the presence of red spots in the face and the presence of this allele in homozygous condition. The same allele was identified in the Derivata di Siria breed. However, its frequency was only 33%, despite the fact that these animals are completely red. The p.267W allele was present in all Murciano-Granadina black goats, whereas it was never identified in the brown ones. Moreover, the same substitution was present in almost all Maltese goats providing evidence of association between this mutation and black coat colour.ConclusionAccording to the results obtained in the investigated goat breeds, MC1R mutations may determine eumelanic and pheomelanic phenotypes. However, they are probably not the only factors. In particular, the surprising not complete association of the nonsense mutation (p.Q225X) with red coat colour raises a few hypotheses on the determination of pheomelanic phenotypes in goats that should be further investigated.

Genetic parameters for early lamb survival and growth in Scottish Blackface sheep.

The objectives of this study were 1) to estimate the heritability of lamb survival and growth in the Scottish Blackface breed; 2) to examine the relationship between lamb survival and live BW; and 3) to investigate the possibility of using lamb survival in a breeding program for this breed. The data used for the analyses contained information about survival and live BW at different ages on 4,459 animals. The records were collected from 1988 to 2003 in a Scottish Blackface flock. Live BW was recorded every 4 wk from birth to 24 wk. Survival was defined either by perinatal or postnatal mortality (up to weaning at 12 wk), or as cumulative survival to 1, 4, 8, and 12 wk. The pedigree file comprised 1,416 dams and 178 sires. A sire model was used to estimate genetic parameters for binary survival traits. Heritabilities of BW traits, and phenotypic and genetic correlations between BW and between survival and BW were estimated by fitting an animal model. Further, correlations of survival with live BW were estimated by using a Markov chain Monte Carlo threshold model, implemented by Gibbs sampling. The heritability estimates for cumulative lamb survival declined from birth onward (from 0.33 to 0.08), and postnatal survival had a heritability of 0.01. The direct and maternal heritabilities for BW traits ranged from 0.08 to 0.26 and from 0.06 to 0.21, respectively, whereas the maternal environmental component was between 0.04 and 0.16. The genetic correlations between BW traits at different ages were high. The genetic and phenotypic correlations between survival and BW were always positive (ranging from 0.04 to 0.54), so there was no antagonism between these traits. Therefore, it is possible to simultaneously improve both survival and live BW in a breeding program for this breed.

Estimation of the genetic and phenotypic variance of several growth traits of the Sicilian Girgentana goat

Abstract The possibility of increasing the age at slaughter of kids, from 25 to 45–60 days, without affecting meat quality, led to this study of the source of variation of several growth traits in the Girgentana goat. Data used in this study were collected between 1998 and 2000 from a total of 276 kids (118 males and 158 females), the progeny of 23 sires and 109 dams. For each individual the identification number, pedigree, sex, body weight at birth and every 15 days up to the age of 60 days and the individual’s maternal litter size were recorded. A sire model was used in order to estimate genetic parameters and correlations between all traits considered, including, in total, 94 animals from 23 sires. This data-set was made up of nine generations. As fixed effects, the mixed sire model included year of birth, age of dam at birth of the offspring and individual’s maternal litter size. Sire within year of birth and the residuals were used as random effects. The genetic correlations between body weight at birth (BW0)/body weight at 30 days (BW30) and body weight at 60 days (BW60) showed the possibility of indirect selection for BW60, by selecting for BW0 or BW30. These genetic correlations with BW60 were 0.86 and 0.90, respectively for BW0 and BW30. Furthermore, body weight heritability ranged from 0.20 to 0.49 at different ages. Average daily gain (ADG) was also considered in four successive 15 day periods starting at birth and up to 60 days (ADG1–4). The ADG heritability estimates were very low and ranged from 0.06±0.026 (ADG2 and 3) to 0.16±0.040 (ADG4). The genetic correlations between ADG1 with 2–4 were negative and tended to zero with increasing age. The phenotypic correlations, on the contrary, increased (from 0.33 to 0.82) with the increase of age. The genetic correlations between BW and ADG traits ranged from −0.32 to 0.93; the phenotypic correlations were lower than the genetic correlations, but showed an analogous trend.

Demographic characterization and genetic variability of the Girgentana goat breed by the analysis of genealogical data

Abstract The aim of this paper is to present an overview of the actual Sicilian Girgentana population structure by the analysis of genealogical data. Statistics show that in 1983 the population consisted of 30,000 Girgentana goats; ten years later almost 98% of the entire Girgentana population disappeared. The remaining population consists of 461 individuals (134 males and 327 females), with 368 living animals. The effective population size is 380 individuals. The inbreeding rate per generation was equal to 0.13%. The average estimated inbreeding level within the living male population was equal to 0.8% (0-15%); and the average inbreeding level within the living female population was equal to 0.7% (0-31%). The average relationship between males and females estimated on 27,772 possible matings was equal to 0.5% (0-8.7%). The estimated inbreeding level was not high due to the lack of pedigree information. This is resulting in a ratio between the number of founder equivalents (ƒe = 22,94) and the number of absolute founders (ƒa = 93) equal to 25%.

The hairless (hr) gene is involved in the congenital hypotrichosis of Valle del Belice sheep

Congenital hypotrichosis in mammalian species consists of partial or complete absence of hair at birth. The hairless gene is often responsible for this disorder in men, mice and rats. Recent experimental data on Valle del Belice sheep reared in Sicily for milk production, support the genetic control of the ovine hypotrichosis as a Mendelian recessive trait. The ovine hairless gene was chosen as the candidate gene involved in this disorder. Blood samples were collected from Valle del Belice sheep with the normal and hypotrichotic phenotypes. Almost the entire hairless gene was successfully amplified using the long PCR technique. Unrelated sheep with differing phenotypes were randomly chosen for sequencing the amplified products. Different mutations related to the hypotrichotic phenotype were found in exon 3. In fact, sequencing revealed an A/T transversion at position 739, a G/A transition at position 823, and a C/T transition at position 1312. From these nucleotide exchanges, three substitutions of the processed mature protein were deduced at the amino acid positions 247 (Thr/Ser), 275 (Ala/Thr), and 438 (Gln/Stop). A PCR-SSCP based test was developed in order to detect the last mutation, which is responsible for the hypotrichotic phenotype.

Comparison between different selection criteria in the genetic evaluation of Valle del Belice sheep

Lactation length in dairy sheep affects milk yield like other genetic and environmental factors. The length of the production period is affected by management decisions such as culling, mating and particularly ranking of animals with different parity and lambing in different months or seasons. Moreover the low heritability of lactation length (Barillet and Boichard, 1987; Dahlin et al., 1998) does not allow its use as a selection criterion. For this reason to achieve a good reliability in phenotypic and genetic evaluation of dairy species, production variability caused by systematic environmental effects must be removed. This is of particular interest for dairy sheep and goats reared in Sicily, where the typical production system is based on pasture, and related food availability is strongly affected by seasonal and annual climatic variations, which results in considerable variations in daily yields........

Comparison of casein haplotypes between two geographically distant European dairy goat breeds

The aim of this paper was to characterize the diversity among haplotypes based on 22 single nucleotide polymorphisms (SNPs) and one deletion within four casein genes in two geographically distant goat populations, the Sicilian Girgentana breed and the Norwegian goat breed. Forty Girgentana goats were genotyped for the aforementioned polymorphisms and the resulting data set was compared with 436 goats from the Norwegian population previously genotyped for these markers. Several casein gene polymorphisms were not in Hardy-Weinberg equilibrium either in Girgentana, or in the Norwegian breed. The SNP haplotype frequencies for the four casein genes were calculated and despite the large geographical distance and phenotypic divergence between these breeds, a proportion of casein loci haplotypes were found to be identical between both Norwegian and Girgentana goats. However, for the CSN2 gene there were no common haplotypes between the two populations. The level of linkage disequilibrium between the casein genes was less in the Girgentana population than in the Norwegian population.

Prion protein gene frequencies in three Sicilian dairy sheep populations

Abstract The objective of this paper was to investigate the prion protein (PrP) genotype and haplotype frequencies in three Sicilian dairy sheep populations. The three populations were: (1) 1096 Valle del Belice animals, (2) 1143 Comisana animals, and (3) 1771 individuals from 5 flocks with scrapie outbreaks, in which the animals were crossbreds derived from indigenous Sicilian dairy breeds. PrP genotypes are described for the three codons 136 (Alanine or Valine; A, V), 154 (Histidine or Arginine; H, R), and 171 (Glutamine, Arginine or Histidine; Q, R, H) which represent polymorphisms known to be linked with scrapie susceptibility. The Valle del Belice haplotype frequencies were 32.3% ARR, 6.5% AHQ, 1.0% ARH, 58.8% ARQ, and 1.4% VRQ. The Comisana frequencies were 39.4% ARR, 2.9% AHQ, 2.9% ARH, 50.9% ARQ, and 3.9% VRQ. In the flocks with scrapie outbreaks the frequencies were 32.8% ARR, 2.4% AHQ, 1.7% ARH, 59.1% ARQ, and 3.9% VRQ. In all three populations ARQ and ARR were the most frequent haplotypes. Multiple generations of strong selection will be needed to fixate the most resistant ARR haplotype.

Effect of weather conditions on somatic cell score in Sicilian Valle del Belice ewes

Abstract Mastitis susceptibility of Valle del Belice ewes from the south of Sicily to temperature, humidity, precipitation, solar radiation, sun hours, air pressure, wind-speed and wind-direction measured by a public weather station was investigated using 65,848 test-day somatic cell score (SCS) records of 5,237 ewes. All weather parameters had an effect on SCS in a regression approach. Extreme values of maximum and minimum temperature-humidity indices resulted in increased SCS. Higher precipitation, solar radiation and sun hours resulted in increased SCS, whereas higher air pressure and wind speed resulted in reduced SCS.

Genetic parameters of fatty acids in Italian Brown Swiss and Holstein cows

The aim of this study was to estimate the genetic parameters and to predict experimental breeding values (EBVs) for saturated (SFA), unsaturated (UFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids, the ratio of fatty acids, and the productive traits in Italian Brown Swiss (BSW) and Holstein Friesian (HOL) cattle. Test-day yields from 235,658 HOL and 21,723 BSW cows were extracted from the Italian HOL and BSW Associations databases from November 2009 to October 2012 out of 3310 herds. The milk samples collected within the routine milk recording scheme were processed with the Milkoscan™ FT 6500 Plus (Foss, Hillerød, Denmark) for the identification of SFA, UFA, MUFA and PUFA composition in milk. Genetic parameters for fatty acids and productive traits were estimated on 1,765,552 records in HOL and 255,592 records in BSW. Heritability values estimated for SFA, UFA, MUFA and PUFA ranged from 0.06 to 0.18 for the BSW breed and from 0.10 to 0.29 for HOL. The genetic trends for the fatty acids were consistent between traits and breeds. Pearson’s and Spearman’s correlations among EBVs for SFA, UFA, MUFA and PUFA and official EBVs for fat percentage were in the range 0.32 to 0.54 for BSW and 0.44 to 0.64 for HOL. The prediction of specific EBVs for milk fatty acids and for the ratio among them may be useful to identify the best bulls to be selected with the aim to improve milk quality in terms of fat content and fatty acid ratios, achieving healthier dairy productions for consumers.