3.4 Positive selection in the macrotis group lineage
A
total of 141 candidate PSGs and 1,274 positively selected sites were
identified with signals of positive selection along each species branch
of the macrotis group based on the branch-site model in PAML 4
(Figure 4, Table 2). Here, 7 hearing-related genes (CRYM ,FOXM1 , PYCARD , SLC52A2 , WRB , MAP6 ,
and SPRY2 ) (Table 3) showed significant evidence of positive
selection in species of the macrotis group. And the positively
selected sites tested in specieslow were
species-specific and distinct from other species (Figure 4, Figure 5a -
Figure 5f). This result may represent different adaptive responses of
auditory development for specieslow. In particular, we
found one hearing-related gene, SPRY2 , was positively selected inR. osgoodi , which emits normal echolocation frequency in themacrotis group. We found same amino acid mutation sites in four
positively selected sites in SPRY2 for R. osgoodi andR. pusillus , which were different from other species (Figure 5g).
The daily activities for bats mainly rely on acoustics, but five
visually related PSGs (ARRDC3 , LZTFL1 , RAB8A ,EGFBPL1 , and TRNT1 ) were tested in
specieslow (Table 4). No visual-related PSG was tested
in speciesnormal.