Transcriptome‐based phylogeny of endemic Lake Baikal amphipod species flock: fast speciation accompanied by frequent episodes of positive selection

Researchers have uncovered evidence of rapid speciation and frequent positive selection in Lake Baikal's endemic amphipod species flock, suggesting adaptive radiation driven by directional selection. Analyzing partial transcriptomes from 64 amphipod species, the study confirmed two independent invasions into the lake and identified parallel evolution of morphological traits like body armor and reduced appendages. Positive selection was more prevalent during the early phase of the second invasion, particularly in genes related to mitochondrial membrane proteins involved in electron transfer and ATP synthesis, hinting at adaptations to planktonic lifestyles and extreme environmental conditions such as low temperatures and high hydrostatic pressures. Other genes under positive selection included Ca-binding muscle-related proteins, potentially adapting to Baikal's calcium-deficient waters.

Naumenko, S. A., Logacheva, M. D., Popova, N. V., Klepikova, A. V., Penin, A. A., Bazykin, G. A., Etingova, A. E., Mugue, N. S., Kondrashov, A. S., & Yampolsky, L. Y. (2017). Transcriptome‐based phylogeny of endemic Lake Baikal amphipod species flock: fast speciation accompanied by frequent episodes of positive selection. Molecular Ecology, 26(2), 536–553. Portico. https://doi.org/10.1111/mec.13927