Scientists find crocodile ‘virgin birth’ at Costa Rica zoo

Source: The post is based on the article “Scientists find crocodile ‘virgin birth’ at Costa Rica zoo”  published in The Hindu on 12th June 2023

What is the News?

Scientists have documented the first-known instance of a “virgin birth” by a crocodile, which had been living in isolation for 16 years at Costa Rican zoo.

The DNA sequences have shown that this was a result of facultative parthenogenesis or reproduction without the genetic contribution of males.

What is facultative parthenogenesis?

Facultative parthenogenesis is the term for when a female can produce offspring either sexually or via asexual reproduction.

How does the virgin birth happen? 

As an egg cell matures in its mother’s body, it divides repeatedly to generate a final product with exactly half the genes needed for an individual. 

Three smaller cellular sacs containing chromosomes, known as polar bodies, are formed as by-products. Polar bodies usually wither away. 

But in vertebrates that can perform parthenogenesis, one polar body sometimes fuses with the egg, creating a cell with the necessary complement of chromosomes to form an individual.

What is the significance of facultative parthenogenesis in crocodiles?

Parthenogenesis has been identified in creatures as diverse as king cobras, sawfish and California condors. But this is the first time it has been found in crocodiles. 

Moreover, because of where crocodiles fall on the Tree of life, it implies that pterosaurs and dinosaurs might also have been capable of such reproductive feats.