MEXICO CITY, June 8 (BNA): Scientists have documented the first known case of a “virgin birth” by a crocodile, who had lived in isolation for 16 years at a Costa Rican zoo, according to a study published Wednesday.
A female American alligator laid 14 eggs in 2018 inside her enclosure, a common phenomenon among captive reptiles. But the most puzzling fact came after three months of incubation when a single egg was found to contain an entire stillborn crocodile, according to Reuters.
According to the study published in the journal Biology Letters, scientists tested the genetic makeup of an alligator embryo. They find a DNA sequence that appears to be the result of selective parthenogenesis (FP), or reproduction without the genetic contribution of a male.
The FP phenomenon, which some scientists have referred to as “virgin birth,” has also been documented in other species of fish, birds, lizards, and snakes. Scientists said this is the first known example in a crocodile.
In FP, a female’s egg cell can develop into a child without being fertilized by a male’s sperm cell.
When making an egg cell, the primary cell divides into four cells: one becomes the egg cell and retains the main cellular structures and jelly-like cytoplasm, while the other cells contain additional genetic material.
Then, one of these cells essentially acts as a sperm cell and fuses with an egg to become “fertilised”.
The American alligator is considered vulnerable and endangered in the wild. According to one hypothesis, the study said, FP may be more common among species on the brink of extinction.
Scientists said the “virgin birth” in Costa Rica could lead to new information about the ancestors of crocodiles who walked the earth in the Triassic period some 250 million years ago.
“This discovery provides exciting insights into the potential reproductive capabilities of the extinct archosaur relatives of crocodiles and birds, particularly members of pterosaurs and dinosaurs,” the study said.
HF