Genome-Wide Analysis of Protein Family Diversity Provides Insights into Species-Specific Protein Family Expansions in Insects

Insects are one of the earliest land animals with more than 400 million years old history on Earth, and they compose more than 80% of species. Insects invade a wide range of ecosystems and are considered one of the most evolutionary successful organism groups. Today, many insect species’ genomes have been sequenced to encode molecular mechanisms behind this magnificent evolutionary plasticity. However, only limited genome-wide studies have been carried out to compare protein family diversity in insects. A total of 20 insect species belonging to seven insect orders and two morphogenesis groups were investigated for evolutionary relationships and to uncover protein family diversity in the present study. The phylogenetic analysis inferred from a total of 530 one-to-one single-copy ortholog genes were separated insects into two evolutionary clades based on morphogenesis. Protein family analyses showed that insects share core protein families that perform essential tasks in development and metabolic processes, such as Pkinase and Zinc Finger, cellular signaling and odorant perception (7tm), digestion of food molecules (Trypsin), and detoxification (p450) with copy number expansion compared to other protein families. Additionally, species-specific protein family expansion was observed in various protein families. This study provided insights into protein family diversity and variation among insects and highlights high copy number variation in protein families species-wide.