A NEW MARKER (NGFB) ON PIG CHROMOSOME-4, ISOLATED BY USING A CONSENSUS SEQUENCE CONSERVED AMONG SPECIES

The nerve growth factor beta gene (NGFB) belongs to a conserved synten ic group on human chromosome 1 and mouse Chromosome 3. The objective o f 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 bas is of a nucleotide sequence comparison among different species, NGFB-s pecific primers were chosen to amplify the corresponding porcine seque nce 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 homologo us with NGFB of other species (mouse, cattle, chicken) and especially with human NGFB; the isolated clone shows 91% nucleotide and 99% trans lated amino acid sequence identity to the human NGFB sequence. The por cine DNA clone allowed us to identify an RFLP marker for genetic mappi ng 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 ha d localized to the same chromosome another member of this syntenic gro up, the gene encoding al Na+,K+ ATPase (ATP1A1). These results show th at a portion of the homologous region between human chromosome 1 and m ouse Chromosome 3 is also conserved on pig chromosome 4.