Evolutionary scenarios of Notch proteins

Area of Science:

• Evolutionary Biology
• Genomics
• Developmental Biology

Background:

• The Notch signaling pathway is crucial for development, involving transmembrane receptors and transcription factors.
• Understanding the evolutionary history of Notch genes provides insights into conserved and divergent biological functions.

Purpose of the Study:

• To reconstruct the evolutionary history of Notch genes across a wide range of species.
• To identify and characterize gene duplication events within the Notch gene family.
• To investigate the evolutionary origins and relationships of different Notch subfamilies, particularly Notch4.

Main Methods:

• Comprehensive phylogenetic analysis of Notch sequences from various species, from invertebrates to vertebrates.
• Comparative genomics to examine gene synteny and identify duplication events.

Main Results:

• Confirmed independent Notch gene duplication in *Caenorhabditis elegans*.
• Identified two major duplication events for vertebrate Notch genes predating teleost and tetrapod divergence.
• Notch2 is phylogenetically closer to Notch3 and emerged during early vertebrate duplications.
• Notch1 duplication in teleosts occurred after divergence from tetrapods.
• Notch4 is mammalian-specific, with origins potentially linked to early chordate whole genome duplications or a recent mammalian duplication event.
• Syntenic gene analysis suggests coordinated evolution of Notch-associated genes (PBX, BRD).

Conclusions:

• The Notch gene family has undergone significant duplication events throughout evolution, shaping its diversity across species.
• The evolutionary trajectory of Notch genes, including the mammalian-specific Notch4, offers insights into functional diversification.
• Further genomic data from diverse vertebrates will refine our understanding of Notch4 evolution and its functional implications.