''Hypsibius dujardini sensu lato'' is a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them . In 1776, th ...

in the class Eutardigrada. A member of this complex, ''Hypsibius exemplaris'', is widely used for various research projects pertaining to

evolutionary biology Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth. In the 1930s, the discipline of evolutionary biolo ...

and

astrobiology Astrobiology (also xenology or exobiology) is a scientific field within the List of life sciences, life and environmental sciences that studies the abiogenesis, origins, Protocell, early evolution, distribution, and future of life in the univ ...

. The species was described by Louis Michel François Doyère in 1840 (as ''Macrobiotus dujardini''). ''H. exemplaris'' was differentiated from ''H. dujardini sensu stricto'' in 2018. Earlier studies refer to this lab species from northwest England as ''H. dujardini''. ''H. dujardini s.s.'' is found in France, and has differences in 18S rRNA sequence and morphological details.

Habitat

The species, ''Hypsibius dujardini'', is a tardigrade that prefers freshwater lakes, rivers, and streams. Because they are considered cosmopolitan, their geographical range is immense. They can be found in regions like the tropics and the poles.

Genome sequencing

The genome of ''Hypsibius exemplaris'' has been sequenced. ''Hypsibius exemplaris'' has a compact genome and a generation time of about two weeks. It can be cultured indefinitely and cryopreserved.

Protection of DNA

''Hypsibius exemplaris'' contains an ortholog of the nuclear protein termed Dsup for damage suppression. Dsup binds to

nucleosome A nucleosome is the basic structural unit of DNA packaging in eukaryotes. The structure of a nucleosome consists of a segment of DNA wound around eight histone, histone proteins and resembles thread wrapped around a bobbin, spool. The nucleosome ...

s and protects

chromatin Chromatin is a complex of DNA and protein found in eukaryote, eukaryotic cells. The primary function is to package long DNA molecules into more compact, denser structures. This prevents the strands from becoming tangled and also plays important r ...

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

from hydroxyl radicals that could be generated by

ionizing radiation Ionizing (ionising) radiation, including Radioactive decay, nuclear radiation, consists of subatomic particles or electromagnetic waves that have enough energy per individual photon or particle to ionization, ionize atoms or molecules by detaching ...

or by

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

References

External links

Tardigrada Newsletter

Tardigrades - Pictures and Movies

The Edinburgh Tardigrade project

Tardigrades (English/German)

Hypsibius dujardini and the evolution of development
{{Taxonbar, from=Q4140844 Hypsibiidae Animals described in 1840