A female stingray recently fell pregnant, despite having no male companions in her tank. What are 'virgin births' and why are they happening more frequently for animals in captivity?
A lone female stingray recently fell pregnant, despite having no male companions in her tank. What are "virgin births" and why are they happening more frequently for animals in captivity?
But that would lead to an unusual shark-stingray hybrid. Instead, some scientists suggested the pregnancy could be the result of a rare phenomenon called parthenogenesis. Stemming from the Greek,meaning "creation", it is where an egg develops into an embryo without being fertilised by sperm. Feldheim developed a paternity test to collect genetic markers called microsatellites. "These are used in human paternity cases, like in shows like CSI and NCIS," he says. The results confirmed that the zebra shark's offspring did not have any paternal DNA – only the female's.
In most cases of animal reproduction, eggs are produced in a process called meiosis, where the cells divide, sharing out genetic material and the other cellular machinery between them. This process generates three cellular offshoots called. Normally, these polar bodies are reabsorbed by the female, but in parthenogenesis, one of those polar bodies can fertilise the egg and form a viable embryo, therefore mimicking sexual reproduction.
For some species, asexual reproduction is advantageous. For example, some populations of whiptail lizard in Mexico and California have become all-female anddoubling the number of chromosomes in the eggs of asexually reproducing females.It is common for mayflies to reproduce through parthenogenesis Lyons was part of an artificial insemination trial in zebra sharks, where scientists studied the chances of survival between sexually produced and parthenogenetic pups. Thefound parthenotes lived on average for a year less, with many displaying behaviour that weakened their chances of survival, such as lopsided swimming, spinning, headstands, and difficulty feeding.
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