Unraveling the Flowerpot Snake's Unique Genome

The flowerpot snake, recognized as one of the smallest snakes globally, possesses some remarkable characteristics. Commonly referred to as the Brahminy blind snake, it is the only known snake species that has three sets of chromosomes instead of the typical two and it can reproduce without a partner.

Researchers at The University of Texas at Arlington are investigating the flowerpot snake’s distinctive genome to understand how this diminutive reptile repairs its DNA and avoids detrimental mutations. Their findings, recently published in the journal Science Advances, offered significant insights into genetic repair mechanisms that may enhance the comprehension of human gene evolution.

This DNA repair and replication activity supports a fascinating mechanism called premeiotic endoreplication, a process through which the snake duplicates its chromosomes before dividing them, sidestepping the need for the typical pairing of chromosomes seen in sexual reproduction. This mechanism allows the snake to produce offspring that are exact genetic clones of itself.”

Matthew Fujita, Biology Professor and Study Co-Author, The University of Texas at Arlington

“For example, we know that having multiple sets of chromosomes is rare for animals, yet flowerpot snakes survive just fine with three instead of the normal two humans have,” Fujita noted.

Utilizing advanced genomic technology, the research team found that the flowerpot snake, which is indigenous to Africa and Asia, possesses 40 chromosomes organized into three subgenomes.

These subgenomes arose from intricate genetic events, including chromosome fusion in ancestral species. The researchers propose that this genetic configuration allows the snake to reproduce without requiring sperm from a male.

A key question the scientists investigated was whether this reproductive method entails any evolutionary disadvantages. Asexual species often face challenges due to the absence of genetic recombination, which is crucial for eliminating harmful mutations over time.

However, the flowerpot snake seems to have developed a mechanism to mitigate this risk. The researchers suggest that its gradual yet consistent evolutionary trajectory helps limit the buildup of harmful mutations.

They also analyzed how genetic variations among different flowerpot snake populations indicate chromosome exchanges between the subgenomes. These exchanges seem to strike a balance between genetic diversity and stability ensuring sufficient variation for adaptation while avoiding incompatibilities that could hinder reproduction.

The study also revealed something unexpected many of the flowerpot snake’s immune-related and sexually selected genes, such as those involved in sperm development, have lost their functions. This finding provides key insights into how reproduction without a mate works in reptiles, but it also reshapes some of our long-held views about the limitations of asexual species. Rather than being an evolutionary ‘dead end’ as researchers have thought, the flowerpot snake shows how nature can innovate and adapt in extraordinary ways.”

Matthew Fujita, Biology Professor and Study Co-Author, The University of Texas at Arlington