Smalltooth sawfish, a species that is threatened with extinction was found to reproduce through ‘virgin births’ or parthenogenesis according to Stony Brook University researchers.
Smalltooth sawfish are an endangered species that have been found to be the first vertebrate not in captivity to reproduce through parthenogenesis. Illegal fishing, overfishing and habitat pollution and destruction have led the sawfish on the brink of being extinct.
Yet, it seems that the conservation instinct drove the females that often cannot find mating partners anymore to assexually reproduce.
Parthenogenesis is aasexual reproduction. An egg is not fecundated by the male’s sperm, but by an identical reproductive cell.
Usually, the offsprings spawned by parthenogenesis are severely impaired and unfit for survival as their genetic material is not sufficiently diverse.
But the colony of smalltooth sawfish found by the research team of Stony Brook University, New York, seemed to be well and thriving. Of the fish, approximately three percent were found to have come from ‘virgin births’ after conclusive DNA testing.
It is reported that for wild vertebrates this is a new mode of reproduction. While parthenogenesis has been observed in vertebrates in captivity before, the case of smalltooth sawfish is a great study point for scientists.
In captivity, some snakes, lizards, fish and insects exhibited the same habit of assexual reproduction. Andrew Fields, lead author of parthenogenesis in smalltooth sawfish study and Ph.D. at Stony Brook University commented that:
“There have been a number of cases in reptiles, birds and sharks of ‘virgin birth’ in captivity. This raises many questions about how common this mode of reproduction is in the wild.”
Perhaps the discovery from the Florida estuary will lead to further research on the matter. The individuals that were found to have come from assexual reproduction exhibited no genetic disadvantage and were not in any way excluded from the bank.
Usually, smalltooth sawfish are strongly connected to the Florida estuaries where they are born and reach a certain point of development at around three years. After which they leave the estuaries to be heading to coastal ocean habitats.
As their numbers are decimated yearly, in 2003 smalltooth sawfish were place under the United States endangered species protection. So far, this alarm signal alone did not draw the attention needed for the sawfish population to be restored.
The researchers hope that the new study and their finding newly emphasizes the need to protect the smalltooth species and make all the necessary efforts to increase and stabilize the population in the Florida estuaries.
Image Source: savethesawfish.com
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