Fossilized cell structures identify an ancient origin for the teleost whole-genome duplication

Abstract

Teleost fishes comprise one-half of all vertebrate species and possess a duplicated genome. This whole-genome duplication (WGD) occurred on the teleost stem lineage in an ancient common ancestor of all living teleosts and is hypothesized as a trigger of their exceptional evolutionary radiation. Genomic and phylogenetic data indicate that WGD occurred in the Mesozoic after the divergence of teleosts from their closest living relatives but before the origin of the extant teleost groups. However, these approaches cannot pinpoint WGD among the many extinct groups that populate this 50- to 100-million-y lineage, preventing tests of the evolutionary effects of WGD. We infer patterns of genome size evolution in fossil stem-group teleosts using high-resolution synchrotron X-ray tomography to measure the bone cell volumes, which correlate with genome size in living species. Our findings indicate that WGD occurred very early on the teleost stem lineage and that all extinct stem-group teleosts known so far possessed duplicated genomes. WGD therefore predates both the origin of proposed key innovations of the teleost skeleton and the onset of substantial morphological diversification in the clade. Moreover, the early occurrence of WGD allowed considerable time for postduplication reorganization prior to the origin of the teleost crown group. This suggests at most an indirect link between WGD and evolutionary success, with broad implications for the relationship between genomic architecture and large-scale evolutionary patterns in the vertebrate Tree of Life.

Extensive lineage-specific rediploidisation masks shared whole genome duplication in the sturgeon-paddlefish ancestor

“…Our estimate that ∼50-66% of the duplicated genome remained tetraploid at the point of the sturgeon-paddlefish divergence i.e. ∼80 million years post-WGD, is much more drawn-out than equivalent estimates for salmonids (∼60-70% rediploidisation completed after ∼50 million years 24,26 ) and teleosts (rediploidisation largely resolved after ∼60 million years 13,64 ) ( Fig. 5, Fig.…”

MicroRNAs as Indicators into the Causes and Consequences of Whole-Genome Duplication Events

“…Second, as argued by Donoghue and Purnell (2005) , correlations between changes to phenotypic complexity (or diversity) and WGDs are only apparent when extant taxa are considered in isolation. When the fossil record is also considered, this apparent correlation breaks down as there is neither a burst of phenotypic innovation nor a change to diversity that could result from any of the WGDs known to have occurred in vertebrate evolution (see also Clarke et al 2016 ; Davesne et al 2021 ).…”

Vasa Is a Potential Germ Cell Marker in Leopard Coral Grouper (Plectropomus leopardus)

“…The genomic synteny analyses showed that the atg3 gene in leopard coral grouper was lost, and the segments contained in ankrd10a , hsf2bp and cryaa occurred through chromosomal translocations, compared to freshwater puffer fish and giant grouper. It could be reasonably inferred that the TSWGD events have shaped the result of the alteration of the gene near Plvasa [ 52 ].…”