A new marker (NGFB) on pig chromosome 4, isolated by using a consensus sequence conserved among species

The nerve growth factor β gene (NGFB) belongs to a conserved syntenic group on human chromosome 1 and mouse Chromosome 3. The objective of this study was the isolation of a part of the porcine NGFB gene and its use as a genetic and physical marker in the pig genome. On the basis of a nucleotide sequence comparison among different species, NGFB-specific primers were chosen to amplify the corresponding porcine sequence by PCR. A pig genomic DNA fragment of 763 bp was isolated, and its DNA sequence, containing the complete coding sequence of mature NGFB, was determined. It was demonstrated that pig NGFB is largely homologous with NGFB of other species (mouse, cattle, chicken) and especially with human NGFB; the isolated clone shows 91% nucleotide and 99% translated amino acid sequence identity to the human NGFB sequence. The porcine DNA clone allowed us to identify an RFLP marker for genetic mapping in pigs and was used to map the NGFB gene to pig chromosome region 4q1.6 → q2.3 by radioactive in situ hybridization. Previously, we had localized to the same chromosome another member of this syntenic group, the gene encoding α₁ Na⁺,K⁺ ATPase (ATP1A1). These results show that a portion of the homologous region between human chromosome 1 and mouse Chromosome 3 is also conserved on pig chromosome 4.