  Scientists have been trying to identify all of the genes in the human genome
since the initial draft of the genome was published in 2001. Over the
intervening years, much progress has been made in identifying protein-coding
genes, and the estimated number has shrunk to fewer than 20,000, although the
number of distinct protein-coding isoforms has expanded dramatically. The
invention of high-throughput RNA sequencing and other technological
breakthroughs have led to an explosion in the number of reported non-coding RNA
genes, although most of them do not yet have any known function. A combination
of recent advances offers a path forward to identifying these functions and
towards eventually completing the human gene catalogue. However, much work
remains to be done before we have a universal annotation standard that includes
all medically significant genes, maintains their relationships with different
reference genomes, and describes clinically relevant genetic variants.
