Editing Genome project (section)

==Time of completion==
When [[Genome sequencing|sequencing]] a genome, there are usually regions that are difficult to sequence (often regions with highly [[repetitive DNA]]). Thus, 'completed' genome sequences are rarely ever complete, and terms such as 'working draft' or 'essentially complete' have been used to more accurately describe the status of such genome projects. Even when every [[base pair]] of a genome sequence has been determined, there are still likely to be errors present because DNA sequencing is not a completely accurate process. It could also be argued that a complete genome project should include the sequences of [[mitochondria]] and (for plants) [[chloroplasts]] as these [[organelles]] have their own genomes.

It is often reported that the goal of sequencing a genome is to obtain information about the complete set of [[genes]] in that particular genome sequence. The proportion of a genome that encodes for genes may be very small (particularly in [[eukaryotes]] such as humans, where [[coding region|coding DNA]] may only account for a few percent of the entire sequence). However, it is not always possible (or desirable) to only sequence the [[coding region]]s separately. Also, as scientists understand more about the role of this [[noncoding DNA]] (often referred to as [[junk DNA]]), it will become more important to have a complete genome sequence as a background to understanding the genetics and biology of any given organism.

In many ways genome projects do not confine themselves to only determining a DNA sequence of an organism. Such projects may also include [[gene prediction]] to find out where the genes are in a genome, and what those genes do. There may also be related projects to sequence [[Expressed sequence tag|ESTs]] or [[mRNA]]s to help find out where the genes actually are.