Study of bovine gene: the temporal-spatial expression patterns, polymorphism and association analysis with meat production traits.

The gene () encodes a transcription factor belonging to the MEF2 family that plays an important role in myogenesis by transcriptional regulation of genes involved in skeletal muscle growth and development. Despite the established importance of the factors in the muscular growth and development, the temporal-spatial expression and biological function of have not been reported in cattle. The aim of this study was to analyze the level of expression in the developing longissimus dorsi muscle (LM) of 4 cattle breeds (Polish Holstein-Friesian [HF], Limousine [LIM], Hereford [HER], Polish Red [PR]), differing in terms of meat production and utility type, at 6, 9, and 12 mo of age. The genetic polymorphism and expression patterns in 6 tissues (heart, spleen, liver, semitendinosus muscle [ST], gluteus medius muscle [GM], and LM) were also investigated. The results showed that mRNA was expressed at a high level in adult skeletal and cardiac muscles. Moreover, expression was markedly greater in the GM than in the LM ( 0.05) and ST ( 0.01). An age-dependent and breed-specific comparison of mRNA level in skeletal muscle of HF, LIM, HER, and PR bulls showed that age was significant differentiating factor of transcript/protein abundance in the LM of HER and LIM ( 0.001) compared to HF and PR, for which the differences in mRNA level were not significant ( > 0.05). Regarding the breed effect on the expression, significantly greater mRNA/protein level was noticed in the LM of 9 and 12 mo-old HER than of LIM ( 0.01), HF ( 0.001), and PR ( 0.001). Four novel SNP, namely, (promoter), (exon 7), (exon 8), and (3'UTR), were identified. We found that 3'UTR variant, situated within the seed region of the miR-5187-3p and miR-6931-5p binding sites, was associated with the level of mRNA/protein in LM of 12-mo-old HF bulls. In addition, we observed a significant association between some carcass quality traits, including meat and carcass fatness quality traits, and various 3'UTR genotypes in the investigated population of HF cattle. Our finding provides new evidence of the significant role in the postnatal muscle growth and development in cattle, and indicates that can be a promising molecular marker for carcass quality-related traits in adult cattle.

Two candidate genes (FTO and INSIG2) for fat accumulation in four canids: chromosome mapping, gene polymorphisms and association studies of body and skin weight of red foxes.

Fat accumulation is a polygenic trait which has a significant impact on human health and animal production. Obesity is also an increasingly serious problem in dog breeding. The FTO and INSIG2 are considered as candidate genes associated with predisposition for human obesity. In this report we present a comparative genomic analysis of these 2 genes in 4 species belonging to the family Canidae - the dog and 3 species which are kept in captivity for fur production, i.e. red fox, arctic fox and Chinese raccoon dog. We cytogenetically mapped these 2 loci by FISH and compared the entire coding sequence of INSIG2 and a fragment of the coding sequence of FTO. The FTO gene was assigned to the following chromosomes: CFA2q25 (dog), VVU2q21 (red fox), ALA8q25 (arctic fox) and NPP10q24-25 (Chinese raccoon dog), while the INSIG2 was mapped to CFA19q17, VVU5p14, ALA24q15 and NPP9q22, respectively. Altogether, 29 SNPs were identified (16 in INSIG2 and 13 in FTO) and among them 2 were missense substitutions in the dog (23C/T, Thr>Met in the FTO gene and 40C/A, Arg>Ser in INSIG2). The distribution of these 2 SNPs was studied in 14 dog breeds. Two synonymous SNPs, one in the FTO gene (-28T>C in the 5'-flanking region) and one in the INSIG2 (10175C>T in intron 2), were used for the association studies in red foxes (n = 390) and suggestive evidence was observed for their association with body weight (FTO, p < 0.08) and weight of raw skin (INSIG2, p < 0.05). These associations indicate that both genes are potential candidates for growth or adipose tissue accumulation in canids. We also suggest that the 2 missense substitutions found in dogs should be studied in terms of genetic predisposition to obesity.

Genetics of fat tissue accumulation in pigs: a comparative approach.

Fatness traits are important in pig production since they influence meat quality and fattening efficiency. On the other hand, excessive fat accumulation in humans has become a serious health problem due to worldwide spread of obesity. Since the pig is also considered as an animal model for numerous human diseases, including obesity and metabolic syndrome, comparative genomic studies may bring new insights into genetics of fatness/obesity. Input of genetic factors into phenotypic variability of these traits is rather high and the heritability coefficient (h(2)) of these traits oscillates around 0.5. Genome scanning revealed the presence of more than 500 QTLs for fatness in the pig genome. In addition to QTL studies, many candidate gene polymorphisms have been analyzed in terms of their associations with pig fatness, including genes encoding leptin (LEP) and its receptor (LEPR), insulin-like growth factor 2 (IGF-2), fatty acid-binding proteins (FABP3 and FABP4), melanocortin receptor type 4 (MC4R), and the FTO (fat mass and obesity-associated) gene. Among them, a confirmed effect on pig fatness was found for a well-known polymorphism of the IGF-2 gene. In humans the strongest association with predisposition to obesity was shown for polymorphism of the FTO gene, while in pigs such an association seems to be doubtful. The development of functional genomics has revealed a large number of genes whose expression is associated with fat accumulation and lipid metabolism, so far not studied extensively in terms of the association of their polymorphism with pig fatness. Recently, epigenomic mechanisms, mainly RNA interference, have been considered as a potential source of information on genetic input into the fat accumulation process. The rather limited progress in studies focused on the identification of gene polymorphism related with fatness traits shows that their genetic background is highly complex.

A comparison of coding sequence and cytogenetic localization of the myostatin gene in the dog, red fox, arctic fox and Chinese raccoon dog.

The gene encoding myostatin (MSTN), due to its crucial function for growth of skeletal muscle mass, is an important candidate for muscularity. In this study we analyzed the nucleotide sequence and FISH localization of this gene in 4 canids, including 3 farm species. The nucleotide sequence of the MSTN coding fragment turned out to be highly conserved, since its identity among the studied species was very high and varied between 99.4 and 99.7%. Only 1, widely spread, silent single nucleotide polymorphism (SNP) was found in exon 1 of the Chinese raccoon dog. The MSTN gene was localized close to the centromere in one-armed chromosomes of the dog (37q11) and bi-armed chromosomes of the red fox (16p11) and arctic fox (10q11), with an exception of the Chinese raccoon dog chromosome (2q14-q21). This chromosome is orthologous to 3 canine chromosomes and thus the MSTN was found more interstitially. Our results are in agreement with the hypothesis that karyotypes of the canids evolved mainly through centric fusion/fission events, while tandem fusions occurred rarely.