Which now seem to serve an as-yet-unknown function in the bat. From ScienceDaily:
Some 18 million years ago, an ancestor of mouse-eared bats “stole” genetic material from an ancient virus related to Bola.
The swiped genetic sequence — a gene called VP35 — has remained largely intact in the bats despite the passage of time, with few changes since it was co-opted, a new study finds. The research also sheds light on the gene’s possible function in bats, suggesting that it may play a role in regulating the immune system’s response to threats.
“We’re using a multidisciplinary approach to understand the evolution, structure and function of a viral gene co-opted by a mammal,” says Derek J. Taylor, PhD, an evolutionary biologist at the University at Buffalo. “From an evolutionary standpoint, it’s rare that you can actually see a viral gene sequence like this that has remained intact in a mammalian host. Most of these things are eroded over time — they get chopped up and shuffled around.
“But VP35 is highly conserved. It’s similar in all the bats we looked at, and the bat versions remain very close to what you see in modern Ebola and Marburg viruses. This conservation suggests that the gene has been preserved for an important purpose.” Paper. (open access) – Megan R. Edwards et al. Conservation of Structure and Immune Antagonist Functions of Filoviral VP35 Homologs Present in Microbat Genomes. Cell Reports, 2018 DOI: 10.1016/j.celrep.2018.06.045 More.
The finding also suggests that Darwinian claims about natural selection as producing evolutionary changes should be tested against the possibility that the change was in fact caused by horizontal gene transfer.
See also: Horizontal gene transfer from tunicates helps beetles against fungus As noted re an earlier story about bats, tThe finding also suggests that Darwinian claims about natural selection producing evolutionary changes should be tested against the possibility that the change was in fact caused by horizontal gene transfer.
Researchers: Cross-species transfer has been “an important driver of evolution”
and
Horizontal gene transfer: Sorry, Darwin, it’s not your evolution any more