Evolutionary dynamics of CRISPR gene drives

Charleston Noble; Jason Olejarz; Kevin Esvelt; George Church; Martin Nowak

doi:10.1101/057281

Home/Archive/bioRxiv

bioRxiv · 10.1101/057281

Evolutionary dynamics of CRISPR gene drives

Charleston Noble·Jason Olejarz·Kevin Esvelt·George Church·Martin Nowak

View original source ↗Export metadata ↓

Abstract

The alteration of wild populations has been discussed as a solution to a number of humanitys most pressing ecological and public health concerns. Enabled by the recent revolution in genome editing, CRISPR gene drives, selfish genetic elements which can spread through populations even if they confer no advantage to their host organism, are rapidly emerging as the most promising approach. But before real-world applications are considered, it is imperative to develop a clear understanding of the outcomes of drive release in nature. Toward this aim, we mathematically study the evolutionary dynamics of CRISPR gene drives. We demonstrate that the emergence of drive-resistant alleles presents a major challenge to previously reported constructs, and we show that an alternative design which selects against resistant alleles greatly improves evolutionary stability. We discuss all results in the context of CRISPR technology and provide insights which inform the engineering of practical gene drive systems.

Source connections

Published article ↗

Explore related subjects

Synthetic Biology Preprint

Keep this discovery

BibTeX RIS

Charleston Noble, Jason Olejarz, Kevin Esvelt, George Church, Martin Nowak. 2016-06-07. Evolutionary dynamics of CRISPR gene drives. https://doi.org/10.1101/057281

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2016

Programming mRNA decay to modulate synthetic circuit resource allocation

Synthetic biomolecular networks embedded in host-cells compete with cellular processes for limited intracellular resources. Resource utilization is a major variable that impacts synthetic circuit behavior. Here we show that intracellular resources could be diverted from cellular operations to a synthetic circuit by programming global mRNA decay using the sequence-dependent endoribonuclease MazF. Synthetic circuit genes were protected from MazF activity by recoding the gene sequence to eliminate recognition sites, while preserving the amino acid sequence. The expression of a protected fluorescent reporter and the metabolic flux of a high-value metabolite gluconate were significantly enhanced using this genome-scale control strategy. Proteomics measurements discovered a key host translation factor in need of protection to optimize the resource redistribution activity. A dynamic computational model demonstrated that the MazF mRNA-decay feedback loop achieved proportional control of MazF levels in an optimal operating regime. RNA-seq time-series measurements of MazF-induced cells elucidated the dynamic shifts in the transcript abundance and discovered regulatory design elements that could be used to expand the control mechanisms of the MazF resource allocator. Together, these results demonstrated that manipulation of resource allocation is a tunable parameter that can be used to redirect resources away from cellular processes to synthetic circuits to enhance target functions.

Synthetic Biology↗

bioRxiv2016

Engineering species-like barriers to sexual reproduction

We introduce a novel approach to engineer a genetic barrier to sexual reproduction between otherwise compatible populations. Programmable transcription factors drive lethal gene expression in hybrid offspring following undesired mating events. As a proof of concept, we target the ACT1 promoter of the model organism Saccharomyces cerevisiae using a dCas9-based transcriptional activator. Lethal over-expression of actin results from mating this engineered strain with a strain containing the wild-type ACT1 promoter.

Synthetic Biology↗

bioRxiv2016

Biosynthesis of the Antibiotic Nonribosomal Peptide Penicillin in Baker’s Yeast

Fungi are a valuable source of enzymatic diversity and therapeutic natural products including antibiotics. By taking genes from a filamentous fungus and directing their efficient expression and subcellular localisation, we here engineer the bakers yeast Saccharomyces cerevisiae to produce and secrete the antibiotic penicillin, a beta-lactam nonribosomal peptide. Using synthetic biology tools combined with long-read DNA sequencing, we optimise productivity by 50-fold to produce bioactive yields that allow spent S. cerevisiae growth media to have antibacterial action against Streptococcus bacteria. This work demonstrates that S. cerevisiae can be engineered to perform the complex biosynthesis of multicellular fungi, opening up the possibility of using yeast to accelerate rational engineering of nonribosomal peptide antibiotics.

Synthetic Biology↗