Shekhovtsov SV, Efremov YR, Poluboyarova TV, Peltek SE. Variation in nuclear genome size within the Eisenia nordenskioldi complex (Lumbricidae, Annelida).
Vavilovskii Zhurnal Genet Selektsii 2021;
25:647-651. [PMID:
34782884 PMCID:
PMC8558923 DOI:
10.18699/vj21.073]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/19/2022] Open
Abstract
The size of the nuclear genome in eukaryotes is mostly determined by mobile elements and noncoding
sequences and may vary within wide limits. It can differ signif icantly both among higher-order taxa and closely
related species within a genus; genome size is known to be uncorrelated with organism complexity (the so-called
C-paradox). Less is known about intraspecif ic variation of this parameter. Typically, genome size is stable within a
species, and the known exceptions turn out be cryptic taxa. The Eisenia nordenskioldi complex encompasses several
closely related earthworm species. They are widely distributed in the Urals, Siberia, and the Russian Far East, as
well as adjacent regions. This complex is characterized by signif icant morphological, chromosomal, ecological, and
genetic variation. The aim of our study was to estimate the nuclear genome size in several genetic lineages of the
E. nordenskioldi complex using f low cytometry. The genome size in different genetic lineages differed strongly,
which supports the hypothesis that they are separate species. We found two groups of lineages, with small
(250–500 Mbp) and large (2300–3500 Mbp) genomes. Moreover, different populations within one lineage also
demonstrated variation in genome size (15–25 %). We compared the obtained data to phylogenetic trees based
on transcriptome data. Genome size in ancestral population was more likely to be big. It increased or decreased
independently in different lineages, and these processes could be associated with changes in genome size and/or
transition to endogeic lifestyle.
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