Last updated February 13, 2018 at 12:59 pm
The rare fish is active, travels widely and, according to a recent study, is in remarkably good health.
The female Amazon molly reproduces clonally. Credit: Bierbach / IGB
The Amazon molly is clearly thriving despite opting for a life without sex.
The finding by a team from Washington University St Louis is surprising given that asexual reproduction is assumed to cause genomes to decay.
However, when the researchers sequenced the Amazon molly’s genome they found few harmful mutations, little genetic decay and a high degree of genetic diversity.
The genome also reveals a remarkable level of variability in genes relating to immunity.
The authors argue that the combination of genetic diversity and broad immune defences might have allowed it to escape the common fate of asexual organisms – being an easy target for pathogens.
All-women warriors
Named after the all-women warriors of Greek mythology, Amazon molly (officially Poecilia Formosa) was the first all-female vertebrate species described back in 1932.
It is a hybrid of two distantly related sexual species and its evolutionary and ecological successes are remarkable.
It has a long existence and has colonised diverse habitats over a wide geographical range.
Asexual vertebrates are extremely rare. There are only about 50 naturally occurring fish, amphibian, and reptile species that reproduce asexually.
The paper was published in Nature Ecology & Evolution.
News of the molly’s marine sexual lifestyle comes less than a week after remarkable new details were revealed about the mutant “marbled crayfish”, which clones itself.
As reported in Cosmos, the 15cm long Procambarus fallax, which did not even exist 25 years ago, has made a fairly significant move out of the aquarium and may be looking to conquer the world.
The New York Times even raised the question of whether cloning isn’t the best strategy. After all, marbled crayfish produce nothing but fertile offspring, allowing their populations to explode.
However, author Carl Zimmer, does conclude that in the long term “there are benefits to sex”.
“Sexually reproducing animals may be better at fighting off diseases, for example. If a pathogen evolves a way to attack one clone, its strategy will succeed on every clone. Sexually reproducing species mix their genes together into new combinations, increasing their odds of developing a defence.”
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