sequencelength

Sequence length is a basic descriptor of a sequence, defined as the number of elements it contains. The term is used across biology, chemistry, and computer science, and the exact unit depends on context: nucleotides for DNA and RNA, amino acids for proteins, or generic symbols in computational sequences.

In biological contexts, sequence length is a fundamental property. For nucleic acids, the length is the count of nucleotides and is often reported in base pairs for double-stranded DNA, or in nucleotides (nt) for single strands. For proteins, length equals the number of amino acids. Sequence length can influence properties such as structural stability, functional domains, and the accuracy of sequence alignment. Ambiguities in sequencing data may be reflected as non-specific bases, which can affect the stated length.

Measurements and data representation vary by source. Sequences generated by sequencing technologies are read as discrete units, and assembled sequences have a length equal to the number of defined positions. Databases typically store a length field alongside the sequence and may annotate partial or gap-containing segments.

In applications, length informs analyses such as alignment, phylogenetics, motif discovery, and comparative genomics. It also affects computational performance, since many algorithms scale with the sequence length. In computing and signal processing, sequence length denotes the number of samples or symbols in a sequence and influences memory usage and processing time.

See also: base pairs, nucleotide, amino acid, contig length, read length, sequence identity.