Scientists from the Virginia Institute of Technology in the United States have for the first time found evidence that crocodiles can lay eggs by facultative parthenogenesis, that is, without mating. Study published in Letters of Biology.
In 2018, an 18-year-old female crocodile, kept at a reptile park in Costa Rica and never mated, laid 14 eggs. Five of them were damaged, the researchers placed the rest of the eggs in an incubator. Not a single cub hatched, but a stillborn female crocodile fetus was found inside an egg.
Scientists examined the fetus and found that it was the result of parthenogenesis, that is, it contained only the mother’s genetic material. In parthenogenesis, females can fuse two of their cells together to produce a viable embryo.
The results obtained by American scientists will help shed light on the evolution of parthenogenesis, as well as give an idea of ​​​​the reproductive abilities of the extinct ancestors of crocodiles – pterosaurs and dinosaurs. The study suggests they had similar abilities, although it is impossible to prove this due to the lack of DNA from ancient lizards.
“If this mechanism (of parthenogenesis) is found in reptiles that are evolutionarily older than archosaurs, that tells us that dinosaurs and pterosaurs most likely interbred with it,” said evolutionary biologist Warren Booth, researcher principal at Virginia Tech. , whose words son ABC news.
Previously, “immaculate conception” in vertebrates was considered a rare event, but scientists have gradually realized that this is not the case. writing Scientific Alert edition. In recent decades, parthenogenesis has been observed in more than 80 animal species, including birds, fish and lizards. In crocodiles, however, it was first discovered.
Parthenogenesis allows the species to reproduce on its own in the absence of a partner for a long time or under unfavorable conditions. However, in some cases, females produce offspring on their own even in the presence of males. Why this happens scientists can’t yet answer, Booth says.
According to the specialist, some individuals born as a result of parthenogenesis can live to adulthood and mate. However, more hardy offspring, as a rule, are obtained as a result of sexual reproduction, writing The New York Times.
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