Author contributions
A.A., N.R., and L.L. designed the study and led the collection of
present-day samples. N.R. initiated and organized the collection of
samples from the 1970s and 1980s, and those samples have been stored in
a frozen tissue bank maintained by N.R. and L.L. at the Department of
Zoology, Stockholm University. S.K. led the laboratory analyses. A.A.
performed population genetics analyses, provided the first draft of the
manuscript, and led the writing with all authors contributing to the
final manuscript.