Comparative genomics of Sarcoptes scabiei provides new insights into
adaptation to permanent parasitism and within-host species divergence
Background: Mites represent the second largest group with
diverse niches and feeding habits, except for insects. Scabies mites are
the causative agents of highly contagious skin disease in humans and
more than 100 mammals. Although several versions of Sarcoptes
scabiei genome have been published, i.e. var. suis, var.
canis and var. hominis, the chromosome-level genome and
population divergence is still desired for the community. Besides, the
molecular mechanisms that scabies mites adapt to a parasitic lifestyle
remains unclear. The taxonomy and ancestral origin of the scabies mite
is unknown. Results: Here, we reported the first
chromosome-level reference genome of S. scabiei, which was
isolated from rabbits. The genome has a contig N50 size of 5.92 Mb, a
total assembled length of 57.30 Mb, and ~12.65% of
repetitive sequences and 9,333 protein‑coding genes were predicted.
Population genetics analysis supported that scabies mites isolated from
different hosts can be subdivided by hosts, and humans are likely the
primary hosts of scabies mites, followed by pigs, dogs, and rabbits.
However, phylogeny results suggested that rabbit was infected with
scabies long before they were domesticated by humans, contradicting
previous hypothesis that humans transmitted scabies mites to animals
through domestication. Comparative genomics between scabies mites and
mites of other feeding habits provided clues concerning the mechanisms
of adaptation to permanent parasitic life from morphology,
detoxification, and metabolism. Conclusions: Together, the
first chromosome-level S. scabiei genome and population genetics
analysis indicated its genetic subdivisions and within-host species
divergence, which also provide evidence for further control of this
highly contagious skin disease.