de novo European eel transcriptome provides insights into the evolutionary history of duplicated genes in teleost lineages
C. Rozenfeld, J. Blanca, V. Gallego, V. García-Carpintero, J.G. Herranz-Jusdado, L. Pérez, J.F. Asturiano, J. Cañizares, D.S. Peñaranda
Abstract
Paralogues pairs are more frequently observed in eels (Anguilla sp.) than in other teleosts.
The paralogues often show low phylogenetic distances; however, they have been
assigned to the third round of whole genome duplication (WGD), shared by all
teleosts (3R), due to their conserved synteny. The apparent contradiction of
low phylogenetic difference and 3R conserved synteny led us to study the
duplicated gene complement of the freshwater eels. With this aim, we assembled de novo transcriptomes of two highly
relevant freshwater eel species: The European (Anguilla anguilla) and the Japanese eel (Anguilla japonica). The duplicated gene complement was analysed in
these transcriptomes, and in the genomes and transcriptomes of other
Actinopterygii species. The study included an assessment of neutral genetic
divergence (4dTv), synteny, and the phylogenetic origins and relationships of
the duplicated gene complements. The analyses indicated a high accumulation of
duplications (1217 paralogue pairs) among freshwater eel genes, which may have originated
in a WGD event after the Elopomorpha lineage diverged from the remaining
teleosts, and thus not at the 3R. However, very similar results were observed
in the basal Osteoglossomorpha and Clupeocephala branches, indicating that the
specific genomic regions of these paralogues may still have been under
tetrasomic inheritance at the split of the teleost lineages. Therefore, two potential
hypotheses may explain the results: i) The freshwater eel lineage experienced
an additional WGD to 3R, and ii) Some duplicated genomic regions experienced
lineage specific rediploidization after 3R in the ancestor to freshwater eels.
The supporting/opposing evidence for both hypotheses is discussed.
PLoS ONE 14(6): e0218085. 2019
doi: 10.1371/journal.pone.0218085
PLoS ONE 14(6): e0218085. 2019
doi: 10.1371/journal.pone.0218085
