DNACHUNKER: Learnable Tokenization for DNA Language Models

Fuente: arXiv
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Main Authors: Kim, Taewon, Shin, Jihwan, Kim, Hyomin, Jung, Youngmok, Lee, Jonghoon, Lee, Won-Chul, Ahn, Sungsoo, Han, Insu
Format: Preprint
Published: 2026
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author Kim, Taewon
Shin, Jihwan
Kim, Hyomin
Jung, Youngmok
Lee, Jonghoon
Lee, Won-Chul
Ahn, Sungsoo
Han, Insu
author_facet Kim, Taewon
Shin, Jihwan
Kim, Hyomin
Jung, Youngmok
Lee, Jonghoon
Lee, Won-Chul
Ahn, Sungsoo
Han, Insu
contents DNA language models are increasingly used to represent genomic sequence, yet their effectiveness depends critically on how raw nucleotides are converted into model inputs. Unlike natural language, DNA offers no canonical boundaries, making fixed tokenizations a brittle design choice under shifts, indels, and local repeats. We introduce DNAChunker, a masked DNA language model that incorporates a learnable adaptive segmentation module to produce context-dependent, variable-length units. Building on a dynamic segmentation procedure, DNAChunker learns to allocate finer granularity to functionally enriched regions while compressing repetitive or redundant sequence. We pretrain DNAChunker on the human reference genome and evaluate it across five benchmarks, where it consistently improves over strong fixed-tokenization baselines. Further analyses and ablations indicate that unlike fixed tokenizations, segmentation is learned in a biologically-informed, mutation-resilient manner.
format Preprint
id arxiv_https___arxiv_org_abs_2601_03019
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DNACHUNKER: Learnable Tokenization for DNA Language Models
Kim, Taewon
Shin, Jihwan
Kim, Hyomin
Jung, Youngmok
Lee, Jonghoon
Lee, Won-Chul
Ahn, Sungsoo
Han, Insu
Genomics
Computation and Language
DNA language models are increasingly used to represent genomic sequence, yet their effectiveness depends critically on how raw nucleotides are converted into model inputs. Unlike natural language, DNA offers no canonical boundaries, making fixed tokenizations a brittle design choice under shifts, indels, and local repeats. We introduce DNAChunker, a masked DNA language model that incorporates a learnable adaptive segmentation module to produce context-dependent, variable-length units. Building on a dynamic segmentation procedure, DNAChunker learns to allocate finer granularity to functionally enriched regions while compressing repetitive or redundant sequence. We pretrain DNAChunker on the human reference genome and evaluate it across five benchmarks, where it consistently improves over strong fixed-tokenization baselines. Further analyses and ablations indicate that unlike fixed tokenizations, segmentation is learned in a biologically-informed, mutation-resilient manner.
title DNACHUNKER: Learnable Tokenization for DNA Language Models
topic Genomics
Computation and Language
url https://arxiv.org/abs/2601.03019