The melanocortin receptor gene family consists of five single-exon members, which are located on autosomes. Three genes (MC2R, MC4R and MC5R) are syntenic in the human, mouse, cattle and dog genomes, while in the pig, the syntenic group comprises MC1R, MC2R and MC5R. Two genes (MC1R and MC4R) have been extensively studied due to their function in melanogenesis (MC1R) and energy control (MC4R). Conservative organisation of these genes in five mammalian species (human, mouse, cattle, pig and dog), in terms of the encoded amino acid sequence, is higher in the case of MC4R compared to MC1R. Polymorphisms of these two genes are responsible or associated with variation of pigmentation (MC1R) and adipose tissue deposition (MC4R). Polymorphic variants in MC1R, causing coat colour variation, were described in humans and domestic mammals (cattle, horse, pig, sheep, dog), as well as farm red and arctic foxes. The MC4R gene is very polymorphic in humans and it is well known that some variants cause monogenic obesity or significantly contribute to the development of polygenic obesity. Such relationships are not so evident in domestic mammals; however, at least one missense substitution (298Asp > Asn) in the porcine MC4R significantly contributes, at least in some breeds, to fat tissue accumulation, feed conversion ratio and daily weight gain. Knowledge on the phenotypic effects of polymorphisms of MC2R, MC3R and MC5R in domestic mammals is scarce, probably due to the small number of reports addressing these genes. Thus, further studies focused on these genes should be undertaken.

Coat colour variation is determined by many genes, one of which is the melanocortin receptor type 1 (MC1R) gene. In this study, we examined the whole coding sequence of this gene in four species belonging to the Canidae family (dog, red fox, arctic fox and Chinese raccoon dog). Although the comparative analysis of the obtained nucleotide sequences revealed a high conservation, which varied between 97.9 and 99.1%, we altogether identified 22 SNPs (10 in dogs, six in farmed red foxes, two in wild red foxes, three in arctic foxes and one in Chinese raccoon dog). Among them, seven appeared to be novel: one silent in the dog, three missense and one silent in the red fox, one in the 3'-flanking region in the arctic fox and one silent in the Chinese raccoon dog. In dogs and red foxes, the SNPs segregated as 10 and four haplotypes, respectively. Taking into consideration the published reports and results of this study, the highest number of missense polymorphisms was until now found in the dog (9) and red fox (7).

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Fatty acid composition in porcine intramuscular fat affects the dietetic value and technological properties of meat. The stearoyl-CoA desaturase (SCD) gene is a strong positional and functional candidate for fatty acid composition. Our sequence analysis in 4 breeds (Duroc, Pietrain, Polish Landrace, and Polish Large White) revealed a novel SNP in the 5'-flanking sequence and 9 novel SNP and 2 novel indels in the 3' untranslated region (UTR). Transcript level of the SCD in subcutaneous fat was significantly greater than in muscle tissue (n=83; P<0.001) and the interbreed comparison revealed a greater transcript level in the fat tissue of Polish Landrace (P<0.01). We found no association between the abundance of the SCD transcript and fatty acid composition in any of the tissues. We performed an association analysis between 4 SNP (c.-353C>T, c.-233T>C, c.*164A>G, and c.*928G>C), 1 indel (c.*2574_2576delGTC), and production traits in Polish Large White (n=185) and synthetic line 990 (n=243). The most pronounced associations were observed for the c.*928G>C polymorphism, which occurs within a predicted target site for 2 microRNA (ssc-miR-185 and ssc-miR-491). In line 990, this polymorphism was significantly associated with daily BW gain (P<0.04 under the general model) and feed conversion ratio (P<0.0004) but not with fatness traits. The same tendency, but not significant, was observed in the Polish Large White breed. When both breeds were analyzed together, these associations were again highly significant (daily BW gain P<0.003; feed conversion ratio P<0.0001). We conclude that c.*928G>C is a promising marker for both porcine traits.

Plant roots are inhabited by an enormous variety of microorganisms, including fungi, which can control the growth as well as regulate the health of the host plants. The mycobiome composition of the roots of wheat plants, especially spelt, under drought stress has been rarely investigated. Therefore, the aim of the present study was to examine the composition of fungal communities in the root endosphere and rhizosphere of three Triticum aestivum ssp. spelta L. cultivars and one Triticum aestivum ssp. vulgare L. cultivar, grown under drought and controlled conditions in different soil preparations. Culture-dependent fungal community profiling was performed to examine the impact of rhizocompartments (endosphere, rhizosphere), host genotype, watering status and different soil preparation on roots mycobiome structure. A total of 117 fungal strains, belonging to 22 genera, were found to colonize the internal and external parts of roots in T. aestivum ssp. spelta L. and T. aestivum ssp. vulgare L. cultivars. The results showed that the part of root and soil preparation type significantly determined the mycobiome composition of wheat roots.