Genomic correlates of disease recovery in natural populations of
mountain yellow-legged frogs
Abstract
In our rapidly changing world, evolution is likely to play an important
role in facilitating the resilience of wildlife populations. The
mountain yellow-legged frog (Rana muscosa/Rana sierrae) provides a rare
example of recovery following severe declines caused by the amphibian
chytrid fungus (Batrachochytrium dendrobatidis). However, the role of
evolution in facilitating this recovery remains circumstantial. In this
study, we sought to gain insights into the potential role of evolution
by comparing genomes of frogs from naïve and recovering populations
located in relatively close proximity. Using multiple methods to scan
frog genomes for signatures of selection, our study reveals several
genomic variants associated with frog recovery. Specifically, we
identify gene variants in interferon-related genes and genes associated
with the complement system and major histocompatibility complex (MHC).
Additionally, we identify a recovery-associated variant in RIN3, a gene
that may play a critical role in disease defense and wound healing.
Finally, we report no differences in genetic diversity between naïve and
recovering populations. We provide a rare example from natural
populations that suggests that evolution can produce individuals that
harbor adaptive alleles and allow population recovery in a novel
environment. These findings complement recent research on amphibian
immune evolution and provide mechanistic hypotheses for how individuals
from populations can recover from disease.