Humans are unique in their capacity for language, but a core component of spoken language is the
ability to learn new vocalizations, and this is shared with only a few other species, including some
bats, birds, cetaceans, pinnipeds, and elephants. Comparative analyses of humans with
other vocal learning species will be key for revealing its biological and evolutionary
underpinnings. To date, vocal learning has been studied extensively in birds. For example,
comparative analyses facilitated by the release of avian genomes have revealed genes with unique
signatures in vocal learning birds. Genome-wide expression analyses have also found that many of
these genes are differentially expressed in vocal learning brain regions, pointing to a link
between these genes and the distinctive vocal abilities of these birds. Mammalian vocal learning
is, by comparison, understudied, particularly at a neurogenetic level. This is largely because of
the scarcity of the trait and the large size and intractability of most vocal learning mammals
(e.g., elephants, whales, dolphins). Their diversity, strong reliance on vocal social
communication, and small size make bats an attractive and experimentally tractable model for
studying vocal learning. Avian research has highlighted shared neurogenetic mechanisms that may
underlie vocal learning across divergent species. Adding bats to this field will bridge the wide
evolutionary gap between birds and humans and will bring us closer to understanding how this
complex behavioral trait can be genetically encoded in the brain. The availability of high-quality
bat genomes will provide a mammalian system in which the biological basis of vocal learning can be
explored and shed light on how this language-relevant trait has evolved across Aves, Mammalia, and
humans. In addition, understanding the genetic bases of language-relevant traits like vocal
learning in bats will help us to understand the genetic causes of disorders involving speech and/or
language (e.g., language disorder, autism, and speech apraxia) in humans. These disorders are
highly prevalent (up to 25% of children) and have a strong genetic component, and understanding
their causes will lead to better genetic diagnoses and new potential therapeutics.
The bat wing is a striking example of morphological adaptation and variation in mammals,
characterized by dramatically elongated fingers and retained interdigital webbing. Several genomic
studies have recently been carried out on developing bat embryonic limbs that identified numerous
candidate wing development–associated genes and regulatory elements. Importantly,
complete genomes are critical to this task, which requires tracking changes in expression encoded
by regulatory regions, and not just protein-coding changes. The Bat1K project would enable
comparative genomic analyses that can highlight specific genes, regulatory elements, and
bat-specific nucleotide changes that are associated with wing development. Characterizing bat wing
development will also improve our understanding of how changes in limb developmental building blocks
can lead to human limb malformations, such as arachnodactyly (long fingers), brachydactyly (short
fingers), and syndactyly (webbed fingers).