Cross species horizontal gene transfer of bacterial genes during human evolution controls human cell proliferation through long non coding RNA’s, and is responsible for gallbladder carcinogenesis.

Abstract Summary Background Gallbladder cancer is the commonest cancer of the bile duct, the etiopathogenesis is still debatable. Non coding RNAs are implicated in various carcinogenesis however their role in gallbladder cancer is still not clear. Methods Transcriptomic data from gallbladder cancer patients was analyzed for differential expression of long non coding RNA (lncRNA), the data was subjected to cross-species phylogenetic analysis and blast with the bacterial and ancient human genome. Pathway analysis, gene-gene interactions and data and text mining was done for non-conserved non coding genes. Findings Of the 16 lncRNA identified as differentially expressed, 7 were found to be phylogenetically of bacterial origin appeared to be acquired by horizontal gene transfer during evolution. These genes were identified in both Homo heidelbergensis and Homo neanderthalensis with dissimilarities. Functional analysis of these gene showed them to regulate various biological and genetic process that appear to promote gallbladder carcinogenesis. Interpretation This is the first study that shows that 7 of the human lncRNA are probably of bacterial origin and has been passed to Homo sapiens through ancestry and part of these has been acquired during human evaluation. These genes regulate the transcription and post transcriptional vital RNA, protein functions and thus may induce gallbladder carcinogenesis.