The fitness landscape of overlapping genes

Fuente: arXiv
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Main Authors: Kirsch, Orson, Wood, Nicole, Redford, Steven A, Husain, Kabir
Format: Preprint
Published: 2026
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author Kirsch, Orson
Wood, Nicole
Redford, Steven A
Husain, Kabir
author_facet Kirsch, Orson
Wood, Nicole
Redford, Steven A
Husain, Kabir
contents Natural genomes sometimes encode two different proteins in staggered reading frames of the same DNA sequence. Despite the prevalence of these 'overlapping genes' across the tree of life, it remains unknown whether arbitrary protein pairs can overlap, to what extent such overlaps are feasible, or what design principles govern them. Here, we study compatibility, frustration, and connectivity in the fitness landscape of overlapping genes. We computationally design sequences de novo that satisfy the dual functional constraints of two distinct protein families. The joint fitness landscape, inferred via Potts models from multiple sequence alignments, reveals a fundamental trade-off between the two proteins and provides a simple criterion for when overlap is feasible. We find widespread compatibility between protein families, with one class of reading frames markedly more permissible than others. By exploring alternative genetic codes, we find that the natural genetic code is uniquely well-suited to support overlapping genes. Constructing mutational paths between sequences, we find that sequence-diverse overlapped genes can be connected via a network of near-neutral mutations. Overall, our results suggest that protein fitness landscapes are sufficiently flexible so as to accommodate the stringent, orthogonal requirements of overlapping genes.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00602
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The fitness landscape of overlapping genes
Kirsch, Orson
Wood, Nicole
Redford, Steven A
Husain, Kabir
Biomolecules
Biological Physics
Populations and Evolution
Natural genomes sometimes encode two different proteins in staggered reading frames of the same DNA sequence. Despite the prevalence of these 'overlapping genes' across the tree of life, it remains unknown whether arbitrary protein pairs can overlap, to what extent such overlaps are feasible, or what design principles govern them. Here, we study compatibility, frustration, and connectivity in the fitness landscape of overlapping genes. We computationally design sequences de novo that satisfy the dual functional constraints of two distinct protein families. The joint fitness landscape, inferred via Potts models from multiple sequence alignments, reveals a fundamental trade-off between the two proteins and provides a simple criterion for when overlap is feasible. We find widespread compatibility between protein families, with one class of reading frames markedly more permissible than others. By exploring alternative genetic codes, we find that the natural genetic code is uniquely well-suited to support overlapping genes. Constructing mutational paths between sequences, we find that sequence-diverse overlapped genes can be connected via a network of near-neutral mutations. Overall, our results suggest that protein fitness landscapes are sufficiently flexible so as to accommodate the stringent, orthogonal requirements of overlapping genes.
title The fitness landscape of overlapping genes
topic Biomolecules
Biological Physics
Populations and Evolution
url https://arxiv.org/abs/2604.00602