Coverage (genetics)

Coverage or depth in genetics refers to the number of times a given nucleotide has been read for sequencing in genetic mapping. While sequencing is highly accurate, the human genome has a vast number of nucleotides and so even a low error rate can produce a significant number of errors if the whole genome is only read once. Repeatedly reading a given area offers the opportunity to eliminate errors there.

In 2011 paper for Genome Research, Ajay et al. arqued that "the current recommendation of ∼30× coverage is not adequate to produce genotype calls across a large fraction of the genome with acceptably low error rates."