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Recombination Signals In The rpoC1 Gene Indicate Gene‐Flow Between Planktothrix (Cyanoprokaryota) Species
Author(s) -
D'Alelio Domenico,
Gandolfi Andrea
Publication year - 2012
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2012.01225.x
Subject(s) - biology , recombination , haplotype , genetics , homologous recombination , gene flow , gene , genbank , evolutionary biology , genetic variation , allele
The delineation of species boundaries in the potentially harmful cyanobacterium P lanktothrix A nagnostidis et K omárek 1988 is particularly tangled. Genetic recombination has been invoked to explain the occurrence of overlapping biological traits among recognized species. Although horizontal gene transfer is shown as a driver of diversification in this genus, clear evidence for homologous recombination at the single gene level is still lacking. Several P lanktothrix strains ( n = 244) sampled in eight fresh water lakes in north I taly were characterized by sequencing the rpoC1 gene, a molecular marker previously proposed to discriminate between species. Six haplotypes were detected, four of which are newly described. A relevant number of rpoC1 sequences ( n = 54) showed evidence of homologous recombination. By comparing the sequences produced in the work presented here to those available on GenBank for the genus, multiple recombination events were tracked between haplotypes associated to P . rubescens , P . suspensa and P . agardhii , the latter being a species not found in our survey. Recombination signals were in form of (i) a vast mosaic structure present in the alignment of rpoC1 haplotypes, (ii) multiple and statistically significant paths in the split decomposition network connecting these haplotypes and (iii) many individual crossing‐over events detected by means of recombination detection tests. Data suggest that the molecular evolution of the rpoC1 gene in the genus P lanktothrix appears as strongly influenced by homologous recombination. In addition, rpoC1 diversity effectively tracks recombinational processes among species in the complex made up by P . rubescens , P . agardhii and P . suspensa , which are not isolated in terms of gene‐flow.