The genome is the complete set of all DNA in an organism. Knowing an organism's genome is extremely useful for genetic, biological, and medical study. A genome is composed of chromosomes. The computerized representation of a genome is an assembly, which is the object created by Arachne.
One important feature of a genome is its size. Most mammalian genomes, including human, are on the order of 1-5 Gbp in length. Bacterial and fungal genomes are much shorter, on the orders of 1-10 Mbp and 10-100 Mbp, respectively. There is no a priori way to know a genome's size (although it is possible to get a reasonable estimate), which can complicate coverage estimations. The input file genome.size gives an estimation of a genome's size.