TLR7 and TLR8 evolution in lagomorphs: different patterns in the different lineages.

Area of Science:

• Immunology
• Evolutionary Biology
• Genetics

Background:

• Toll-like receptors (TLRs) are crucial innate immune sensors for pathogen recognition.
• TLR7 and TLR8 specifically detect single-stranded RNA (ssRNA) and have diverse evolutionary patterns across vertebrates.
• Mammalian TLR7 and TLR8 are generally conserved, with notable exceptions in lagomorphs.

Purpose of the Study:

• To investigate the evolutionary trajectory of TLR7 and TLR8 genes within the mammalian order Lagomorpha.
• To analyze the expression patterns of TLR7 and TLR8 in key lagomorph species, specifically the European rabbit and hares.

Main Methods:

• Searched public sequence databases for TLR7 and TLR8 genes.
• Performed evolutionary analyses to trace gene duplication and loss events.
• Evaluated gene expression levels of TLR7 and TLR8 in lagomorphs.

Main Results:

• Confirmed the absence of TLR8 in hares and its wide expression in European rabbits.
• Identified the absence of TLR7 in European rabbits and significant divergence in hares.
• Observed accelerated evolution of TLR7 and TLR8 in lagomorphs compared to other mammals.

Conclusions:

• Lagomorph TLR7 and TLR8 genes exhibit rapid and distinct evolutionary patterns, particularly within the leporid family.
• These evolutionary dynamics may be influenced by historical viral interactions and the genes' location in dynamic telomeric regions.