Echolocation is a complex phenotypic trait that has evolved independently
in bats and whales, and which involves the production, reception
and auditory processing of ultrasonic pulses for obstacle avoidance,
orientation and hunting. Recent phylogenetic studies have shown
that echolocating bats are not a true group—one lineage also contains
the non-echolocating Old World fruit bats (family Pteropodidae), indicating
that echolocation has evolved at least twice in bats, or was lost
early in the evolutionofOldWorld fruit bats.New evidence supports
the former scenario: divergent clades of echolocating bats seem to have
undergone convergent amino acid replacements in several genes implicated in
hearing. Furthermore, some candidate hearing genes also
show parallel changes in echolocating bats and whales, again suggesting roles
in high-frequency hearing. Other genes that might
function in echolocation have been identified from screens for selection in bat
and cetacean sequence data. Here, using the evolution of
echolocation as a model of phenotypic convergence, we investigated the
extent to which parallel changes have occurred across the genome during
the independent evolution of echolocation in bats and cetaceans.
We undertook genome sequencing of four divergent bat species,
including both echolocating and non-echolocating forms. From the
proposed suborder Yinpterochiroptera we sequenced the greater horseshoe bat
Rhinolophus ferrumequinum and the greater false vampire
bat Megaderma lyra, which exhibit ‘constant frequency’ (CF) and
‘frequency modulated’ (FM) echolocation, respectively (for details of
calls, see refs ). From this suborder we also sequenced the nonecholocating
straw-coloured fruit bat Eidolon helvum, to which we
added published draft genome data from a second non-echolocating
fruit bat, the large flying fox Pteropus vampyrus. From the second suborder,
Yangochiroptera, we sequenced the CF echolocating Parnell’s
moustached bat Pteronotus parnellii, and added published data from
the FM echolocating little brown bat Myotis lucifugus.