Experiments showed that artificially splitting TnpB's reRNA into two parts could convert it into a CRISPR-like system, enabling it to utilize guide RNAs from CRISPR arrays, marking a pivotal step in CRISPR evolution.

Further engineering confirmed that this split reRNA approach was sufficient to transform TnpB into a functional CRISPR-like system.

Genomic analysis identified 146 TnpB-like proteins and uncovered six intermediate clades called TranCs, which represent evolutionary stages between TnpB nucleases and Cas12.

Phylogenetic and structural studies, including AlphaFold modeling, delineated these six TranC clades as key intermediates in the transition from transposon systems to CRISPR immunity.

The research traced the evolutionary lineage of these proteins, revealing their significance in the development of CRISPR systems.

Understanding this molecular evolution enhances our capacity to develop advanced genetic engineering technologies with potential applications in medicine and agriculture.

Functional assays discovered that some TranC systems utilize dual-guide RNAs—both intrinsic CRISPR RNAs and transposon-derived reRNAs—indicating their role as evolutionary intermediates.

A novel dual-guide RNA mechanism was identified, representing an evolutionary step towards the complex guide systems seen in modern CRISPR-Cas systems.

These systems demonstrate how dual-guide RNA mechanisms can facilitate DNA targeting, highlighting the evolutionary sophistication of these intermediate systems.

Recent research from Chinese scientists has shed light on the molecular evolution of Type V CRISPR-Cas systems, especially focusing on Cas12, a powerful genome editing tool.

The study highlights that the diversification of RNAs derived from transposons played a crucial role in this evolution, emphasizing RNA-level innovations over changes in protein structure.

Findings demonstrate that RNA innovations can transform TnpB proteins into CRISPR-like systems capable of guiding DNA targeting, offering new avenues for engineering smaller, versatile genome editing tools.

The research also explores how transposon activity, involving TnpB nucleases and their relation to Cas12 effectors, contributed to the emergence of CRISPR immunity systems.