The smallest organisms found on Earth can be determined according to various aspects of organism size, including volume, mass, height, length, or genome size. Given the incomplete nature of scientific knowledge, it is possible that the smallest organism is undiscovered.
Largest and Smallest Genome in the World. ... Smallest genome identified is from a Viroid family, Viroids are the smallest known pathogenic agents and on of the smallest belongs to the Grapevine ...
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase.The nucleic acid is usually double-stranded DNA (dsDNA) but may also be single-stranded DNA (ssDNA). DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses. Single-stranded DNA is usually expanded to double-stranded in infected cells.
$\begingroup$ The plant and bacterial ones I had floating around in my memory having read about them previously, so a bit of googling confirmed the names. The animal ones I got from the Animal Genome Size DB, and from Wikipedia. I guessed that viral genomes would be the smallest, so I also searched for the smallest viral genome.
hypothesized that single-stranded virus are smaller because that type of molecule is more fragile than the double stranded molecule. This is generally true for both ssDNA and ssRNA viruses. Some ssDNA genomes can be as small as 1300 nt in length, whereas the minimal genome size of a sequenced ssRNA virus is 2300 nt.
The second smallest non-viral genome is found in Nanoarchaeum equitaans, a thermophilic archaea found among hydrothermal vents on the Atlantic Ocean floor, around the Mid-Atlantic Ridge. N. equitaans is a highly unusual organism, lacking certain metabolic pathways found in practically every other living thing, and being given its own phylum in domain Archaea.
Genome Sizes. The genome of an organism is the complete set of genes specifying how its phenotype will develop (under a certain set of environmental conditions). In this sense, then, diploid organisms (like ourselves) contain two genomes, one inherited from our mother, the other from our father.
Some of the smallest RNA viruses, retroviruses such as the Rous sarcoma virus, have genomes 3,500 base pairs in length, a diameter of about 80 nm, and only possess just four genes. The smallest DNA viruses have a smaller size (18-26 nm) but larger genomes, around 5,000 base pairs.
Try our new, experimental Virus Sequence Search Interface and send us your feedback! Learn more about this tool at NCBI Insights.
Start studying Bio 261 Chapter 9 Viral Genomes and Diversity. Learn vocabulary, terms, and more with flashcards, games, and other study tools.