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The evolution of insect Metallothioneins

Citation

Luo, Mei et al. (2020), The evolution of insect Metallothioneins, Dryad, Dataset, https://doi.org/10.5061/dryad.pc866t1mh

Abstract

Metallothioneins (MTs) are a family of cysteine-rich metal-binding proteins that are important in the chelating and detoxification of toxic heavy metals. Until now, the short length and the low sequence complexity of MTs has hindered the inference of robust phylogenies, hampering the study of their evolution. To address this longstanding question, we applied an iterative BLAST search pipeline that allowed us to build a unique dataset of more than 300 MT sequences in insects. By combining phylogenetics and synteny analysis, we reconstructed the evolutionary history of MTs in insects. We show that the MT content in insects has been shaped by lineage-specific tandem duplications from a single ancestral MT. Strikingly, we also uncovered a sixth MT, MtnF, in the model organism Drosophila melanogaster. MtnF evolves faster than other MTs and is characterized by a non-canonical length and higher cysteine content. Our methodological framework not only paves the way for future studies on heavy metal detoxification but can also allow us to identify other previously unidentified genes and other low complexity genomic features.

Funding

AgBioResearch, Michigan State University, Award: MICL02522

National Natural Science Foundation of China, Award: 31760637, 31640064

China Scholarship Council, Award: 201708360095