Aditi Merchant
adititm.bsky.social
Aditi Merchant
@adititm.bsky.social
BioE PhD student @ Stanford in the Hie Lab // ML for Synthetic Biology
This was all possible because of the support of my incredible PI @brianhie.bsky.social and my amazing labmates @samuelhking.bsky.social and Eric Nguyen. Grateful to be surrounded by people who inspire me to be a better scientist.

To learn more, check out the paper: www.nature.com/articles/s41...
Semantic design of functional de novo genes from a genomic language model - Nature
By learning a semantics of gene function based on genomic context, the genomic language model Evo autocompletes DNA prompts to generate novel genes encoding protein and RNA molecules with defined acti...
www.nature.com
November 19, 2025 at 4:40 PM
Together, this work suggests that genomic sequence models can meaningfully generalize beyond characterized natural evolution. Looking forward, we hope that semantic design can serve as a starting point for function-guided design and optimization of genes across biology.
November 19, 2025 at 4:37 PM
Beyond providing novel sequences for functions of interest, SynGenome can be used to predict the roles of domains of unknown function, reveal functional associations across prokaryotic biology, and catalog chimeric proteins with unique domain combinations generated by Evo.
November 19, 2025 at 4:37 PM
Semantic design achieved high experimental success rates (up to 50%) without structural conditioning or fine-tuning. To explore semantic design more broadly, we created SynGenome, a database of generations from millions of prompts spanning 9 thousand functional terms.

evodesign.org/syngenome/
SynGenome
100 billion base pairs of AI-generated genomic sequence
evodesign.org
November 19, 2025 at 4:36 PM
Next, we designed anti-CRISPR (Acr) proteins. Evo generated functional Acr proteins that protected against spCas9, despite some having no sequence or predicted structural similarity to known Acrs. This further supported the idea Evo could generalize based on context alone.
November 19, 2025 at 4:35 PM
We next asked if semantic design could co-design more evolutionarily diverse sequences. Focusing on toxin–antitoxin systems, we successfully generated a functional RNA antitoxin, a de novo toxic gene, and broadly neutralizing antitoxins. Many had <30% sequence identity to nature.
November 19, 2025 at 4:35 PM
We first tested if Evo understands genomic context. Given partial sequences of conserved genes, we show that Evo can achieve near-perfect amino acid sequence recovery and complete entire operons bidirectionally, all while still producing diverse underlying DNA sequences.
November 19, 2025 at 4:34 PM
Genomic language models like Evo can leverage this: by prompting with natural genomic context containing genes related to a function of interest, we can ‘autocomplete’ sequences with novel, diverse generations enriched for similar functions. We call this semantic design.
November 19, 2025 at 4:34 PM
Just as word meaning emerges from context—"you shall know a word by the company it keeps"—prokaryotic gene function is tied to genomic context. This notion of guilt by association, where related genes cluster in operons, has led to the discovery of many molecular tools like CRISPR, BGCs, and more.
November 19, 2025 at 4:33 PM
In recent years, we’ve seen immense progress in leveraging generative AI to accelerate biological design. However, using these models to produce diverse sequences with desired high-level functions remains challenging.
November 19, 2025 at 4:32 PM
If you’re interested in learning more or have any questions or feedback, definitely reach out! The preprint, along with a link to the PDF (since bioRxiv seems to be having some server issues) are linked below! N/N

www.biorxiv.org/content/10.1...

evodesign.org/Semantic_Min...
www.biorxiv.org
December 19, 2024 at 6:54 PM
This work was a massive collaborative effort between my amazing fellow graduate students Samuel King and Eric Nguyen! And of course, none of this would have happened without the incredible mentorship of @brianhie.bsky.social! Very fortunate to work with such inspiring scientists daily :) 13/N
December 19, 2024 at 6:54 PM
Ultimately, this study suggests that biological sequence models may be able to nontrivially generalize beyond known evolutionary space and that prompt engineering can be a valuable tool for steering generation towards desired functional outcomes. 12/N
December 19, 2024 at 6:54 PM
SynGenome is publicly available at evodesign.org/syngenome/. You could use SynGenome to find diversified natural proteins, functionally characterize uncharacterized genes, or find highly divergent proteins with potentially conserved functions. We’re excited to see what the community can find! 11/N
SynGenome
100 billion base pairs of AI-generate genomic sequence
evodesign.org
December 19, 2024 at 6:54 PM
To generate SynGenome, we used prompts derived from the genes encoding prokaryotic proteins in UniProt, reasoning that the resultant generations may be enriched for functions related to the proteins the prompts were derived from. 10/N
December 19, 2024 at 6:54 PM
Finally, to apply semantic mining to generate functional genes from across prokaryotic biology, we developed SynGenome, a database containing over 120 billion base pairs of synthetic DNA sequences. 9/N
December 19, 2024 at 6:54 PM
Despite this high diversity, 17% of the Acr designs we tested were functional. Additionally, many of our experimentally validated Acrs had low confidence AF3 structure predictions and two eluded significant structural or sequence characterization, making them akin to “de novo” genes (!) 8/N
December 19, 2024 at 6:54 PM
We then applied semantic mining to see if we could design new anti-CRISPR (Acr) proteins, a highly diverse group of proteins with limited sequence or structural conservation thought to sometimes emerge via de novo gene birth. 7/N
December 19, 2024 at 6:54 PM
Half of the Evo-designed antitoxins we experimentally tested were functional (!), with most possessing only remote homology to natural proteins and some appearing to neutralize diverse toxin classes. 6/N
December 19, 2024 at 6:54 PM
We then applied semantic mining to generate a multi-gene bacterial toxin-antitoxin (TA) system. Using context from known TA systems as prompts, we first designed and experimentally validated a toxin gene. This toxin gene then served as a prompt for Evo to generate new conjugate antitoxins. 5/N
December 19, 2024 at 6:54 PM