Differences in lateral gene transfer in hypersaline versus thermal environments.

Area of Science:

• Microbial Evolution
• Genetics
• Environmental Microbiology

Background:

• Lateral gene transfer (LGT) plays a crucial role in microbial evolution, with distant transfer events offering significant fitness advantages.
• Microbial transformation is a key mechanism driving long-distance LGT, enabling gene exchange between diverse species.
• Thermophiles and halophiles are known for their high rates of LGT.

Purpose of the Study:

• To investigate inter-class lateral gene transfer events in thermophilic (Thermoprotei) and halophilic (Halobacteria) archaea.
• To compare the origins of transferred genes in these two distinct archaeal classes.

Main Methods:

• Identification of inter-class LGT events in Thermoprotei and Halobacteria.
• Categorization of transferred genes based on their origin (thermophilic or halophilic).

Main Results:

• Identified inter-class LGT events into both thermophilic and halophilic archaeal classes.
• Over 68% of LGT events into Thermoprotei originated from other thermophiles.
• Less than 11% of LGT events into Halobacteria originated from other halophiles, suggesting significant influx from non-halophilic sources.

Conclusions:

• A fundamental difference exists in LGT patterns between thermophiles and halophiles.
• Environmental factors, such as DNA degradation in thermal environments versus DNA preservation and debris collection in hypersaline environments, likely drive these differences.
• Halophiles are theoretically exposed to a greater diversity and quantity of extracellular DNA, facilitating more varied LGT.