RT Journal
A1 uz-Zaman, Md. Hassan
A1 Ochman, Howard
T1 De novo gene birth and the conundrum of ORFan genes in bacteria
JF Genome Research 
JO Genome Research 
YR 2025 
FD August 01 
VO 35 
IS 8 
SP 1679 
OP 1688 
DO 10.1101/gr.280157.124 
UL http://genome.cshlp.org/content/35/8/1679.abstract 
AB Bacterial genomes are notable in that they contain large numbers of lineage-restricted (“ORFan”) genes, which have been postulated to originate from either horizontal transfer, rapid divergence from pre-existing genes, or de novo emergence from noncoding sequences. We assess the body of research that explores each of these hypotheses and demonstrate that the mystery of the origin of bacterial ORFans still remains unresolved. Nonetheless, bacteria offer several unique avenues for research into the process and mechanics of gene birth at a resolution not feasible in other organisms. Both their amenability to experimental evolutionary analysis and their strain-level variation in gene content foster investigations of how noncoding sequences acquire expression and transition into functionality—questions central to the origin of phenotypic novelty.