Coevolution of Drosophila-type timeless with partner clock proteins

Area of Science:

• Evolutionary biology
• Chronobiology
• Molecular biology

Background:

• Drosophila-type timeless (dTIM) is crucial for circadian rhythms and light entrainment in fruit flies.
• Its role and evolutionary trajectory vary significantly across different insect species.

Purpose of the Study:

• To conduct a comprehensive phylogenetic analysis of dTIM across diverse animal groups.
• To determine the evolutionary history, including origin, duplication, and loss events of dTIM.
• To identify key protein domains and animal lineages exhibiting substantial dTIM evolution.

Main Methods:

• Phylogenetic analysis of dTIM across a broad range of animals.
• Dating of gene origin, duplication, and loss events.
• Identification of conserved and variable protein domains within dTIM.

Main Results:

• dTIM evolution is largely independent of PER protein changes, even with PER loss in echinoderms.
• dTIM modifications consistently correlate with the loss of CRYPTOCHROMES or JETLAG.
• Accelerated dTIM evolution observed in phylloxera and aphids.
• Alternative dTIM splicing, linked to temperature-dependent function in Drosophila, shows partial conservation in Diptera with unique modifications.

Conclusions:

• The study highlights major evolutionary events shaping dTIM across the animal kingdom.
• dTIM evolution is intricately linked to the presence/absence of CRYPTOCHROMES and JETLAG.
• Understanding dTIM evolution provides insights into the diversification of circadian clock mechanisms.