Jokubka R, Maak S, Kerziene S, Swalve H H
Department of Animal Breeding and Genetics, Lithuanian Veterinary Academy, Kaunas, Lithuania.
J Anim Breed Genet. 2006 Feb;123(1):17-22. doi: 10.1111/j.1439-0388.2006.00559.x.
The melanocortin 4 receptor is expressed in virtually all brain regions of mammals and plays an important role in energy homeostasis. Polymorphisms in this gene may thus be related to growth and obesity. In pigs, a non-synonymous polymorphic site was described (Asp298Asn) and demonstrated to affect cAMP production and to alter adenylyl cyclase signalling. Association studies revealed significant linkage of this mutation with production trait in pigs. In this study, 207 Lithuanian White pigs were genotyped at the MC4R locus and analysed on relationships between genotype and breeding values for several performance traits. The observed allele and genotype frequencies did not deviate significantly from Hardy-Weinberg equilibrium (wildtype allele 0.59; mutant allele 0.41) and are comparable with those described in other Large White populations. The mutant Asn298 allele of the MC4R gene was significantly associated with increased test daily gain, higher lean meat percentage and lower backfat thickness. There was a trend towards an improved feed conversion ratio (p = 0.065) in animals with the mutant allele whereas no significant effect was found on lifetime daily gain. These results indicate that the MC4R polymorphism should be integrated in selection programmes in the Lithuanian White to improve carcass composition.
黑皮质素4受体在哺乳动物几乎所有脑区均有表达，且在能量稳态中发挥重要作用。因此，该基因的多态性可能与生长和肥胖有关。在猪中，已描述了一个非同义多态性位点（Asp298Asn），并证明其会影响cAMP的产生并改变腺苷酸环化酶信号传导。关联研究表明，该突变与猪的生产性状存在显著连锁。在本研究中，对207头立陶宛白猪的MC4R基因座进行了基因分型，并分析了基因型与几个生产性能性状育种值之间的关系。观察到的等位基因和基因型频率与哈迪-温伯格平衡无显著偏差（野生型等位基因0.59；突变等位基因0.41），且与其他大白猪群体中描述的频率相当。MC4R基因的突变型Asn298等位基因与日增重增加、瘦肉率提高和背膘厚度降低显著相关。携带突变等位基因的动物有饲料转化率提高的趋势（p = 0.065），而对终生日增重未发现显著影响。这些结果表明，MC4R多态性应纳入立陶宛白猪的选择计划中，以改善胴体组成。
