Cross-contamination explains "inter- and intraspecific horizontal genetic transfers" between asexual bdelloid rotifers
File(s)
Supporting information
Published version
Author(s)
Wilson, CG
Nowell, Reuben
Barraclough, Timothy
Type
Journal Article
Abstract
A few metazoan lineages are thought to have persisted for millions of years without sexual reproduction. If so, they would offer important clues to the evolutionary paradox of sex itself [1, 2]. Most "ancient asexuals" are subject to ongoing doubt because extant populations continue to invest 17 in males [3–9]. However, males are famously unknown in bdelloid rotifers, a class of microscopic invertebrates comprising hundreds of species [10–12]. Bdelloid genomes have acquired an unusually high proportion of genes from non-metazoans via horizontal transfer [13–17]. This well-substantiated finding has invited speculation [13] that homologous horizontal transfer between bdelloid individuals also may occur, perhaps even "replacing" sex [14]. In 2016, Current Biology published an Article claiming to supply evidence for this idea. Debortoli et al. [18] sampled rotifers from natural populations and sequenced one mitochondrial and four nuclear loci. Species assignments were incongruent among loci for several samples, which was interpreted as evidence of "interspecific horizontal genetic transfers". Here, we use sequencing chromatograms supplied by the authors to demonstrate that samples treated as individuals actually contained two or more highly divergent mitoc hondrial and ribosomal sequences, revealing cross-contamination with DNA from multiple animals of different species. Other chromatograms indicate contamination with DNA from conspecific animals, explaining genetic and genomic evidence for "intraspecific horizontal exchanges" reported in the same study. Given the clear evidence of contamination, the data and findings of Debortoli et al. [18] provide no reliable support for their conclusions that DNA is transferred horizontally between or within bdelloid species.
Date Issued
2018-08-06
Date Acceptance
2018-05-23
Citation
Current Biology, 2018, 28 (15), pp.2436-2444.e14
ISSN
1879-0445
Publisher
Elsevier
Start Page
2436
End Page
2444.e14
Journal / Book Title
Current Biology
Volume
28
Issue
15
Copyright Statement
©2018 The Authors. Published by Elsevier Ltd.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Sponsor
Natural Environment Research Council (NERC)
Natural Environment Research Council (NERC)
Grant Number
NE/J01933X/1
NE/M01651X/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
Cell Biology
MISMATCH REPAIR
SEQUENCE DIVERGENCE
MEIOTIC SEX
DEGENERATE TETRAPLOIDY
TRANSPOSABLE ELEMENTS
CONVERSION EVENTS
DNA-SEQUENCES
RECOMBINATION
EVOLUTION
BACTERIA
DNA contamination
asexual reproduction
data accuracy
genomics
homologous recombination
horizontal gene transfer
molecular evolution
polymerase chain reaction
reproducibility of results
scientific experimental error
06 Biological Sciences
11 Medical and Health Sciences
17 Psychology and Cognitive Sciences
Developmental Biology
Publication Status
Published
Date Publish Online
2018-07-12