Range of a Palearctic uraniid moth Eversmannia exornata (Lepidoptera: Uraniidae: Epipleminae) was split in the Holocene, as evaluated using histone H1 and COI genes with reference to the Beringian disjunction in the genus Oreta (Lepidoptera: Drepanidae)

Abstract

Large-scale climatic cycling during the Pleistocene resulted in repeated split and fusion of species ranges in high northern latitudes. Disjunctions of ranges of some Eurasian species associated with nemoral communities used to be dated to ‘glacial time’, with existence of their contiguous ranges reconstructed not later than 1 mya, while a recent hypothesis associates them with the Boreal time of the Holocene and reconstructs the contiguous ranges ca 5 thousand years ago. These estimates differing by almost 3 orders of magnitude appealed for their testing via molecular methods. We made such a test for Eversmannia exornata (Lepidoptera: Uraniidae: Epipleminae), the only uraniid moth inhabiting Siberia, the range of which is split into three pieces: East European, West Siberian and Far Eastern. Two genes were sequenced in specimens from one population from each geographical isolate: a fragment of the mitochondrial cytochrome c oxydase I (COI), frequently used for molecular phylogeny and barcoding, and a nuclear gene encoding histone H1. The COI gene fragment appeared to have two alleles differing by one synonymous substitution; both alleles co-occurring in the European population. The histone H1 gene had two dimorphic synonymous sites, with both variants of one site found in all three isolates. Absence of accumulated difference in both genes and polymorphism for the same synonymous substitution in the H1 gene in all three parts of the range suggests a very recent disjunction which cannot be resolved by coding gene sequences. This well corresponds to the Holocene disjunction hypothesis and rules out the Pliocene/early Pleistocene disjunction hypothesis. The published rate of the COI gene evolution was verified using the Beringian disjunction in the genus Oreta (Lepidoptera: Drepaniidae) as comparing two northernmost Asian and one American species which diverged not later than the Pliocene. The rate of substitution accumulation in the histone H1 gene was estimated as 0.48 of that of the COI gene, that is ca 3.6 × 10−9 substitutions per site per year. Four indels were found in the histone H1 gene in the three Oreta species studied, differing from each other not less than with two indels.