Cells with minimal genome can evolve as fast as normal cells

Cells with minimal genome can evolve as fast as normal cells

Subject :Science and technology

Section: Biotechnology

Introduction

• Dairy farming introduced gene mutations in humans to digest milk.
• Mutations in non-essential genes can drive evolution in complex organisms.
• Challenge: How does a simple organism with essential genes evolve with minimal targets for selection?

Experimental Setup: 

• Mycoplasma mycoides Genome (Sourced from goat, cattle gut)
• Created minimal cell (Mycoplasma mycoides JCVI-syn3.B) with 493 genes compared to non-minimal cell (JCVI-syn1.0).
• Genome minimization reduced minimal cell fitness by over 50%.

Testing Evolution

• Minimal and non-minimal cells grown separately for 300 days, equivalent to 40,000 years of human evolution.
• Minimal cells showed mutation rates comparable to non-minimal cells.
• Despite the minimal cell’s reduced fitness due to genome minimization, the researchers found that it could evolve as fast as a normal cell.

Comparison and Genetic Pathways

• Size difference: Non-minimal cells increased by 80%, while minimal cells remained the same size.
• Examination of genomes of adapted cells reveals distinct genetic pathways.

Significance of Findings

• Significant contribution to microbial evolution.
• Relevance to synthetic biology and the adaptability of engineered cells.
• Life’s robustness and adaptability even with minimal genomes.
• Implications for treating clinical pathogens, engineered microorganisms, and the origin of life.

Key terms:

• Gene Mutation: A gene mutation is a permanent alteration in the DNA sequence that makes up a gene. Mutations can result from changes in the nucleotide sequence of DNA and can lead to variations in an organism’s characteristics.
• Evolution: Evolution is the process by which species change over time through the gradual accumulation of genetic changes. It leads to the development of new species from pre-existing ones.
• Genome: A genome is the complete set of an organism’s genetic material, including all of its genes and non-coding sequences of DNA.
• Synthetic Biology: Synthetic biology is an interdisciplinary field that combines principles from biology, engineering, and computer science to design and construct new biological parts, devices, and systems, or to redesign existing biological systems for useful purposes.
• Minimal Cell: A minimal cell is a simplified version of a biological cell that contains only the essential genes and components required for life.
• Natural Selection: Natural selection is the process by which organisms with traits that confer a reproductive advantage in a given environment are more likely to survive, reproduce, and pass on their genes to the next generation.
• Fitness: Fitness in an evolutionary context refers to an organism’s ability to survive, reproduce, and pass on its genes to the next generation. It is a measure of how well an organism is adapted to its environment.
• Genetic Variation: Genetic variation refers to the diversity of genetic material within a population. It arises from mutations, genetic recombination, and other processes and is a source of genetic diversity within a species.