What is a chromosome?
located in nucleoid, carries essential genes
What is a chromid?
the intermediate: uses plasmid partitioning system, carries essential genes
What is a plasmid?
uses plasmid partitioning system, carries nonessential genes
What do prokaryotic genomes form?
supercoil domains with protein cores
Are prokaryote genomes compact?
yes: high gene density, little non-coding repetitive sequences, many contain clustered regularly interspaced short palindromic repeats (CRISPR)
How do different prokaryotic genomes compare?
the size and number of genes varies dramatically
What do metagenomics study?
all genomes in a sample: not all bacteria can be cultured or isolated, DNA can be extracted from a sample & sequenced (environmental: dirt, sea water, car bumper, biological: gut microbiome, skin microbiome)