Researchers at a zoo in Costa Rica have found an unmatched case of a crocodile who made herself pregnant. This resulted in the advancement of a fetus that shared a 99.9% hereditary resemblance with its mother. The phenomenon has been observed in birds, fish, and other reptiles but this is the very first time it has actually been recorded in crocodiles.
Image credit: Wikipedia Commons.
In 2018, a solitary female American crocodile (Crocodylus acutus) that had actually been residing in captivity for 16 years stunned scientists by laying a clutch of eggs, one consisting of a fetus, a female like her mother. Hereditary analysis now showed the crocodile produced the eggs with no input from a male, a procedure typically referred to as virgin birth.
While the eggs didnt hatch, the finding suggests that crocodiles ancient family members, the dinosaurs, might have shared these reproductive capabilities.
Birds and crocodiles belong to a group of reptiles called archosaurs, which forms a distinct clade.
How did this happen?
“Given that (virgin births) can happen in the presence of prospective mates, circumstances of this might be missed out on when recreation occurs in females co-habited with males,” they wrote.
A crocodile egg cell undergoes multiple departments, resulting in a final product carrying only half of the necessary genetic material. At the same time, 3 smaller cellular sacs are formed as byproducts, usually predestined to deteriorate. One of these sacs periodically merges with the egg, forming a cell with a complete set of chromosomes.
The study was published in the journal Biology Letters.
The scientists propose in their paper that virgin births could be more widespread among crocodiles, yet have stayed unnoticed due to the absence of concentrate on such incidents.
Virgin births such as this one have been observed in over 80 vertebrate types, consisting of lizards, sharks, rays, and snakes. Nevertheless, the majority of these occurred within captive animal populations. While scientists initially believed this was something unusual, they slowly realized that virgin births, or parthenogenesis, were more widespread than formerly believed.
By carrying out genomic sequencing on tissues drawn out from both the fetuss heart and the mothers shed skin, the scientists established a striking 99.9% similarity between the two. This offered unequivocal evidence that the offspring was produced through asexual reproduction, with no contribution from a male parent.
Mammals stay the main exception. Unlike reptiles, fish, and birds, mammalian embryo formation requires a process known as genomic imprinting. This system involves specific genes from both the dad and the mother being activated and shut off at accurate timings, helping with the development of the embryo.
This is likely what occurred with the crocodile in Costa Rica, the scientists stated. When the group at the zoo observed it had laid eggs, they called Warren Booth, a scientist at Virginia Tech, who recommended nurturing them. When none hatched, the group opened the eggs and found among them consisted of a completely formed, however lifeless, female fetus.
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Birds and crocodiles belong to a group of reptiles called archosaurs, which forms an unique clade. A crocodile egg cell undergoes numerous divisions, resulting in a last product bring just half of the necessary hereditary material. This is likely what happened with the crocodile in Costa Rica, the researchers said.
Researchers at a zoo in Costa Rica have discovered an unprecedented case of a crocodile who made herself pregnant. The phenomenon has actually been observed in birds, fish, and other reptiles but this is the first time it has been recorded in crocodiles.
