Comparative transcriptomics reveals the evidence of genetic adaptations
in the macrotis group (Chiroptera: Rhinolophidae)
Abstract
Understanding the adaptive evolution of species has long interested
evolutionary biologists. Adaptive phenotypes can result from changes in
protein-coding sequences that affect protein structure and function. The
Rhinolophus macrotis group as a specific group has low echolocation
frequency relative to body size compared with other rhinolophids,
suggesting a special evolutionary process of this group. Transcription
bridges genetic information and phenotypes. Here, we sequenced
transcriptomes of the brain, liver, and cochlea for five species of the
macrotis group and its closely related species, R. pusillus, to explore
the molecular basis of the adaptation in the macrotis group at the
sequence level. Strong and significant positive selection signals for
species within the macrotis group was detected in seven genes (CRYM,
FOXM1, MAP6, PYCARD, SLC35A2, WRB and SPRY2) linked to hearing.
Unexpectedly, we also detected five PSGs (ARRDC3, LZTFL1, RAB8A, IGFBPL1
and TRNT1) linked to vision in species with relatively low frequencies.
These results suggested that natural selection has led to the positive
selection of some sensory-related genes. Furthermore, PSGs identified in
the macrotis group significantly enriched in GO categories related to
metabolism (e.g. catalytic activity and oxidoreductase activity), which
provided evidence to parse the genetic adaptations of the species with
low frequencies within the macrotis group. This is the first attempt to
detect genome-wide sequence evolution across the macrotis group and our
study provided valuable resources for studying the genetic mechanisms of
rhinolophids adaptation.