Genome

A genome is the complete set of genetic material present in an organism or cell. It includes genes and the noncoding sequences of the genome, as well as regulatory elements and the genetic material found in organelles such as mitochondria and chloroplasts.

Genome organization varies by life form. In bacteria and archaea, genomes are typically a single circular chromosome; in eukaryotes, genomes consist of multiple linear chromosomes in the nucleus accompanied by organellar genomes. The genome contains coding regions that produce proteins or functional RNA, as well as introns (in many eukaryotes), regulatory sequences, repetitive elements, noncoding RNA genes, and pseudogenes.

Genome size is highly variable and is measured in base pairs or large units (bp, Mb, Gb). Bacterial genomes are usually a few million base pairs, whereas the human diploid genome is about 6.4 Gb. Many plant genomes are even larger. Genome size does not always correlate with organismal complexity.

Genomic sequencing and analysis refer to determining the order of bases and interpreting the functional elements. Sequencing projects produce reference genomes, which serve as standards for a species, and pangenomes that capture diversity. Annotation identifies genes, regulatory regions, and other features. Comparative genomics studies evolution and biology.

Applications include medicine, agriculture, and biotechnology. Genomic data support diagnosis, personalized medicine, crop improvement, and fundamental research. The field also raises ethical, legal, and social considerations related to privacy, data sharing, and the use of genomic information.