Digital Screening And Identiifcation Of Teratogenic Genes Underlying Beak Deformity In Chickens

In various indigenous chicken breeds, there are low frequencies (about1-3%) of beak deformity(crossed beaks). This phenomenon severely impacts production by decreasing feed intake. This studysought to differentially screen genes in normal birds and those with deformed beaks using digital geneexpression together with qPCR technology. First, the main chemical constituents of chicken beaks weremeasured, using national standard methods. Second, differentially-expressed genes were filtered usingdigital gene expression methods by comparing RNA expression in deformed beaks and normal-shapedbeaks in full-sibs. Third, the expression profiles of an up-regulated gene LOC426217anddown-regulated gene MUC were established. The results and conclusions were as follows:1. The rhamphothecas was mainly protein (93.32%); in bony sections, there was38.7%protein,20.7%ether extract and34.86%ash. These results suggested that beak deformity might be related todisorders of protein and fat metabolism.2. When gene expression was compared in deformed and normal beaks, there were1156differentially expressed genes,409up-regulated and747down-regulated the differentially expressedgenes were concentrated in chromosomes LGE64and25. Using GO enrichment analysis, thedifferentially expressed genes were significantly enriched in the cytoskeleton GO term, which containedmany keratin family members in chromosome25. Differentially expressed genes were also significantlyenriched in pathways of unsaturated fatty acid biosynthesis and glycerol acid metabolism pathway.Subsequent validation tests, using qPCR, essentially confirmed the trends shown by digital geneexpression sequencing. From these results, candidate genes which could be linked with the deformedbeaks were selected for further research: BMP4, LOC426217, LFNG, MUC, ACAA1, ALDH7A1, etc.The unsaturated fatty acid biosynthesis pathway and glycerol acid metabolism pathways could be targetpathways in the development of beak deformity.3. The expression of LOC426217was high in beak, but relatively low in other tissues, suggestingthat the LOC426217gene performed a tissue-specific function in beak; LOC426217may be a genedeserving of further research.