Chromosomal assignment of the ovine hairless (hr) gene by fluorescence in situ hybridization.

Congenital hypotrichosis in mammalian species consists of partial or complete absence of a hair coat at birth. Affected individuals having a partial hair coat at birth may loose it subsequently.The aim of this paper was to physically map the ovine hr gene using fluorescence in situ hybridization (FISH).A preliminary study on an internet data bank (http://www.informatics.jax.org) showed that the regions of the hr gene on murine chromosome 14 and human chromosome 8 present homology with ovine chromosome 2

Survey of milk protein polymorphism in the "Bovina Rossa Siciliana"

The “Rossa Siciliana” is an autochthonous small Sicilian dairy cattle population, accounting for 5-7,000 individuals.This breed is characterized by high ability to live on poor pasture lands, moderate milk production, and traditionally linked to cheese production. Aim of this work was to investigate milk protein polymorphisms in this population. A total of 62 individual milk samples were collected from 19 extensive farms spread in the “Parco dei Nebrodi” area (Messina). All samples were analyzed by isoelectrofocusing (IEF) with pH range 2.5-6. High variability was found at the CSN1S1, CSN2, CSN3, LGB and LALBA loci, while the CSN1S2 locus was monomorphic for the A allele. The allele frequencies and the Hardy-Weinberg equilibrium were estimated using the GENEPOP software, further the casein haplotype frequencies and the occurrence of the linkage disequilibrium were computed with the EH software, taking into account the association among loci. Joint analysis at all loci showed that the population is not in Hardy-Weinberg equilibrium (Chi-square=19.0, pvalue=0.0407), probably due to genetic drift. Of the three alleles detected at CSN1S1 locus, CSN1S1*B and CSN1S1*C had high frequencies (0.734 and 0.258 respectively), as reported for most breeds. The CSN1S1*D allele was detected with a low frequency (0.008). High frequencies were found for CSN2*A2 (0.573) and CSN3*B (0.637). High frequencies were observed for LALBA*B (0.903) and LGB*B (0.815). Strong linkage disequilibrium was detected for the polymorphic casein loci CSN1S1-CSN2-CSN3. For the casein haplotype only the hypothesis of association among loci was considered. Out of the 27 expected, only four haplotypes had a frequency higher than 0.10. The most frequent haplotype was BA2B (0.236), followed by CA2B (0.214), BA1A (0.168), BA1B (0.131), and BA2A (0.094). The high frequency of BA2B haplotype and the possible relation with production traits are under investigation

Phylogenetic analysis of Sicilian goats reveals a new mtDNA lineage

The mitochondrial hypervariable region 1 (HVR1) sequence of 67 goats belonging to the Girgentana, Maltese and Derivata di Siria breeds was partially sequenced in order to present the first phylogenetic characterization of Sicilian goat breeds. These sequences were compared with published sequences of Indian and Pakistani domestic goats and wild goats. Mitochondrial lineage A was observed in most of the Sicilian goats. However, three Girgentana haplotypes were highly divergent from the Capra hircus clade, indicating that a new mtDNA lineage in domestic goats was found

Genotype by environment interaction in Nelore cattle from five Brazilian states

Records from 75,941 Nelore cattle were used to determine the importance of genotype by environment interaction (GEI) in five Brazilian states. (Co)variance components were estimated by single-trait analysis (with yearling weight, W450, considered to be the same trait in all states) and multiple-trait analysis (with the record from each state considered to be a different trait). The direct heritability estimates for yearling weight were 0.51, 0.39, 0.44, 0.37 and 0.41 in the states of Goiás, Mato Grosso, São Paulo, Mato Grosso do Sul and Minas Gerais, respectively. The across-state genetic correlation estimates between Goiás and Mato Grosso, Goiás and Minas Gerais, São Paulo and Minas Gerais, and Mato Grosso do Sul and Minas Gerais ranged from 0.67 to 0.75. These estimates indicate that GEIs are biologically important. No interactions were observed between Goiás and São Paulo, Goiás and Mato Grosso do Sul, Mato Grosso and São Paulo, Mato Grosso and Mato Grosso do Sul, Mato Grosso and Minas Gerais, or São Paulo and Mato Grosso do Sul (0.82 to 0.97). Comparison of single and multiple-trait analyses showed that selection based on the former was less efficient in the presence of GEI, with substantial losses (up to 10%) during selection

Bayesian inference in genetic parameter estimation of visual scores in Nellore beef-cattle

The aim of this study was to estimate the components of variance and genetic parameters for the visual scores which constitute the Morphological Evaluation System (MES), such as body structure (S), precocity (P) and musculature (M) in Nellore beef-cattle at the weaning and yearling stages, by using threshold Bayesian models. The information used for this was gleaned from visual scores of 5,407 animals evaluated at the weaning and 2,649 at the yearling stages. The genetic parameters for visual score traits were estimated through two-trait analysis, using the threshold animal model, with Bayesian statistics methodology and MTGSAM (Multiple Trait Gibbs Sampler for Animal Models) threshold software. Heritability estimates for S, P and M were 0.68, 0.65 and 0.62 (at weaning) and 0.44, 0.38 and 0.32 (at the yearling stage), respectively. Heritability estimates for S, P and M were found to be high, and so it is expected that these traits should respond favorably to direct selection. The visual scores evaluated at the weaning and yearling stages might be used in the composition of new selection indexes, as they presented sufficient genetic variability to promote genetic progress in such morphological traits

QTL detection by multi-parent linkage mapping in oil palm (Elaeis guineensis Jacq.)

A quantitative trait locus (QTL) analysis designed for a multi-parent population was carried out and tested in oil palm (Elaeis guineensis Jacq.), which is a diploid cross-fertilising perennial species. A new extension of the MCQTL package was especially designed for crosses between heterozygous parents. The algorithm, which is now available for any allogamous species, was used to perform and compare two types of QTL search for small size families, within-family analysis and across-family analysis, using data from a 2 × 2 complete factorial mating experiment involving four parents from three selected gene pools. A consensus genetic map of the factorial design was produced using 251 microsatellite loci, the locus of the Sh major gene controlling fruit shell presence, and an AFLP marker of that gene. A set of 76 QTLs involved in 24 quantitative phenotypic traits was identified. A comparison of the QTL detection results showed that the across-family analysis proved to be efficient due to the interconnected families, but the family size issue is just partially solved. The identification of QTL markers for small progeny numbers and for marker-assisted selection strategies is discussed