A Colon Cancer Related Gene-MLH1, Significantly Affecting the Pig Litter Size

MutL homolog 1, colon cancer, nonpolyposis type 2 (MLH1) is a tumor related gene. In this study, the full-length cDNA sequence of porcine MLH1 gene was cloned through rapid amplification of cDNA ends (RACE) method. The porcine MLH1 gene encodes a protein of 757 amino acids which shares high homology with the MLH1 of five species: chiru (96%), sheep (95%), cattle (93%), southern-white-rhinoceros (92%) and goat (92%). This novel porcine gene was assigned to GeneID: 100337665. Phylogenetic analysis revealed that the porcineMLH1 gene has a closer genetic relationship with theMLH1 gene of southern- white-rhinoceros. PCR-HhaI-RFLP was established to detect GU373696:c.395 G > A substitution of porcine MLH1 gene and eight pig breeds display obvious genotype and allele frequency differences at this mutation locus. Association of this SNP with litter size traits was assessed in Large White (n = 200) and Landrace (n = 200) pig populations, and result demonstrated that this polymorphic locus was significantly associated with the litter size of all parities in Large White and Landrace sows (P < 0.01). Therefore, MLH1 is also a reproduction related gene.