S. solfataricus is a species of thermophilic archaeon that belongs to the genus Saccharolobus (formerly Sulfolobus). It is found in volcanic hot springs and other acidic environments where it can grow at temperatures around 80°C and pH levels between 2 and 4. It is a model organism for studying archaeal biology, especially DNA replication, transcription, and translation.
What are the possible relatives of S. solfataricus?
To answer this question, we need to look at the phylogenetic relationships of S. solfataricus with other archaeal species. One way to do this is to compare the sequences of their ribosomal RNA (rRNA) genes, which are highly conserved and can reflect the evolutionary history of organisms. Based on rRNA analysis, S. solfataricus belongs to the phylum Thermoproteota, which is one of the two major groups of Crenarchaeota (the other being Thaumarchaeota). Within Thermoproteota, S. solfataricus is classified in the class Thermoprotei, the order Sulfolobales, and the family Sulfolobaceae.
The closest relatives of S. solfataricus are other members of the genus Saccharolobus, such as S. acidocaldarius, S. islandicus, S. tokodaii, and S. caldissimus. These species share more than 90% similarity in their rRNA sequences and have similar morphological and physiological characteristics. They also have similar genome sizes and structures, with a single circular chromosome and many mobile genetic elements.
Other relatives of S. solfataricus are other members of the order Sulfolobales, such as Acidianus, Metallosphaera, Stygiolobus, and Sulfurisphaera. These species have less than 90% similarity in their rRNA sequences with S. solfataricus, but still share some common features, such as being thermoacidophiles, having spherical or lobed cells, and using sulfur or organic compounds as energy sources. However, they also have some differences, such as having different cell wall compositions, metabolic pathways, or genome architectures.
Beyond the order Sulfolobales, the relatives of S. solfataricus become more distant and diverse. They include other members of the class Thermoprotei, such as Thermofilum, Pyrobaculum, Thermoproteus, Caldivirga, and Vulcanisaeta; and other members of the phylum Thermoproteota, such as Desulfurococcus, Ignicoccus, Pyrodictium, Staphylothermus, and Aeropyrum. These species have less than 80% similarity in their rRNA sequences with S. solfataricus and have different ecological niches, cell shapes, or metabolic modes. They also belong to different orders or families within Thermoproteota.
Conclusion
In conclusion, the most closely related species to S. solfataricus are other members of the genus Saccharolobus (formerly Sulfolobus), followed by other members of the order Sulfolobales within the class Thermoprotei and the phylum Thermoproteota. These relationships are based on rRNA sequence comparisons and supported by morphological, physiological, and genomic data.
