Mechanism and potential routes for the evolution of the bacterial CO2-concentrating mechanism. (A) Today, the bacterial CCM functions through the concerted action of three primary features – (i) an inorganic carbon (Ci) transporter at the cell membrane, and (ii) a properly-formed carboxysome structure (iii) co-encapsulating rubisco with carbonic anhydrase (CA). Ci uptake leads to a high intracellular HCO3− concentration, well above equilibrium with the external environment. Elevated HCO3− is converted to a high carboxysomal CO2 concentration by CA activity located only there, which promotes carboxylation by rubisco. (B) Mutants lacking genes coding for essential CCM components grow in elevated CO2 but fail to grow in ambient air, as shown here for mutations to the α-carboxysome in the proteobacterial chemoautotroph H. neapolitanus. Strains lacking the carboxysomal CA (ΔcsosCA) or an unstructured protein required for carboxysome formation (Δcsos2) failed to grow in ambient air, but grew robustly in 5% CO2 (>108 colony-forming units/ml) (C) We consider the CCM to be composed of three functionalities beyond rubisco itself: a CA enzyme (magenta), a Ci transporter (dark brown), and carboxysome encapsulation of rubisco with CA (light brown). If CO2 levels were sufficiently high, primordial CO2-fixing bacteria would not have needed a CCM. We sought to discriminate experimentally between the six sequential trajectories (dashed arrows) in which CCM components could have been acquired. Credit: Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2210539119
Cyanobacteria are single-celled organisms that derive energy from light, using photosynthesis to convert atmospheric carbon dioxide (CO2) and liquid water (H2O) into breathable oxygen and the carbon-based molecules like proteins that make up their cells. Cyanobacteria were the first organisms to…
2023-01-31 16:37:04 Genetic engineering sheds light on ancient evolutionary questions
Source from phys.org In recent years, genetic engineering has revolutionized our understanding of the natural world, unlocking a wealth of answers to complex evolutionary questions. As scientists learn more about the genetic structures of organisms, they can deduce more subtle information about the ancestral relationships of these species and the mechanisms of their genetic diversification.
The field of genetic engineering is full of successes that stretch far beyond understanding evolutionary relationships. Through targeted modification of an organism’s genetic sequence, scientists can create more efficient crops, more resilient animals and higher-yielding organisms. By manipulating an organism’s DNA to favor specific traits, genetic engineering has produced new strains of crops that can resist drought, pests, and other environmental hazards.
But perhaps most importantly, genetic engineering has provided a powerful tool for reconstructing the history of organisms. By comparing the DNA of different species, scientists can create “family trees” of related species. Similarly, researchers can use genetic data to identify important traits that distinguish one species from another, such as the relationship between humans and chimpanzees or how modern wolves descended from ancient wolves.
In the past, scientists used fossils and other evidence to understand evolutionary relationships, but the accuracy of this method was limited. Genetic engineering has allowed researchers to unlock precise information about exactly how organisms have evolved over time, revealing patterns of diversity and interrelatedness that weren’t previously apparent.
In short, genetic engineering has become one of the most essential tools in the analysis of evolutionary relationships. By deciphering strands of DNA, researchers can understand not only the basics of biotic relationships, but also the mechanisms and processes of speciation. Moreover, genetic engineering provides a powerful tool for further understanding and exploring our evolutionary past. As continued advancements in genetic engineering technology provide more data, biologists can continue to uncover new and exciting information about the evolution of life on Earth.