Anabaena is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of filament

Filament

-In physics and electrical engineering:* An electrical filament used to emit light in an Incandescent light bulb* Similarly, a thin heating element* Current filament* Filament propagation, diffractionless propagation of a light beam...

ous cyanobacteria that exists as plankton

Plankton

Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

. It is known for its nitrogen fixing abilities, and they form symbiotic

Symbiosis

Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...

 relationships with certain plants, such as the mosquito fern

Mosquito fern

Azolla is a genus of seven species of aquatic ferns in the family Salviniaceae. They are extremely reduced in form and specialized, looking nothing like conventional ferns but more resembling duckweed or some mosses.-Selected species:Azolla caroliniana Willd.   [ Poss. synon...

. They are one of four genera of cyanobacteria that produce neurotoxin

Neurotoxin

A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...

s, which are harmful to local wildlife, as well as farm animals and pets. Production of these neurotoxins is assumed to be an input into its symbiotic relationships, protecting the plant from grazing

Grazing

Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...

 pressure.

A DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 sequencing

Sequencing

In genetics and biochemistry, sequencing means to determine the primary structure of an unbranched biopolymer...

 project was undertaken in 1999, which mapped the complete genome

Genome

In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 of Anabaena, which is 7.2 million base pairs long.