Isozymes of a tunicate and a cephalochordate as a test of polyploidisation in chordate evolution

Schmidtke, Jörg; Weiler, Conrad; Kunz, B.; Engel, Wolfgang

doi:10.1038/266532a0

Cited by 23 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, two (or more) separate polyploidizations may have occurred in the advance to the vertebrate grade. Schmidtke et al, (1977) surveyed twelve enzymes in a single tunicate species (Ciona intestinalis) and a single cephalochordate species (Branchiostoma lanceolarum). Of the seven enzyme systems which they could resolve, they found evidence of gene duplication in only one -malate dehydrogenase.…”

Section: Discussionmentioning

confidence: 99%

Evolution of five multilocus isozyme systems in the chordates

et al. 1980

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Evolution of five multilocus isozyme systems in the chordates

et al. 1980

View full text Add to dashboard Cite

“…Indeed, while teleosts are considered to have doubled their genes in relation to humans (see below), chromosomal loss, or diploidization [16], [17] seems to have been rampant in this group, since similar numbers exist between teleosts (∼20–25) and rodents and primates (19–22 autosomes). As a result, the number of WGD, and whether such events have occurred at all, has remained controversial [9], [12], [15], [18], [21]–[25].…”

Section: Introductionmentioning

confidence: 99%

Vertebrate Vitellogenin Gene Duplication in Relation to the “3R Hypothesis”: Correlation to the Pelagic Egg and the Oceanic Radiation of Teleosts

2007

View full text Add to dashboard Cite

The spiny ray-finned teleost fishes (Acanthomorpha) are the most successful group of vertebrates in terms of species diversity. Their meteoric radiation and speciation in the oceans during the late Cretaceous and Eocene epoch is unprecedented in vertebrate history, occurring in one third of the time for similar diversity to appear in the birds and mammals. The success of marine teleosts is even more remarkable considering their long freshwater ancestry, since it implies solving major physiological challenges when freely broadcasting their eggs in the hyper-osmotic conditions of seawater. Most extant marine teleosts spawn highly hydrated pelagic eggs, due to differential proteolysis of vitellogenin (Vtg)-derived yolk proteins. The maturational degradation of Vtg involves depolymerization of mainly the lipovitellin heavy chain (LvH) of one form of Vtg to generate a large pool of free amino acids (FAA 150–200 mM). This organic osmolyte pool drives hydration of the ooctye while still protected within the maternal ovary. In the present contribution, we have used Bayesian analysis to examine the evolution of vertebrate Vtg genes in relation to the “3R hypothesis” of whole genome duplication (WGD) and the functional end points of LvH degradation during oocyte maturation. We find that teleost Vtgs have experienced a post-R3 lineage-specific gene duplication to form paralogous clusters that correlate to the pelagic and benthic character of the eggs. Neo-functionalization allowed one paralogue to be proteolyzed to FAA driving hydration of the maturing oocytes, which pre-adapts them to the marine environment and causes them to float. The timing of these events matches the appearance of the Acanthomorpha in the fossil record. We discuss the significance of these adaptations in relation to ancestral physiological features, and propose that the neo-functionalization of duplicated Vtg genes was a key event in the evolution and success of the teleosts in the oceanic environment.

show abstract

“…In Ohno's original proposal, lancelet and vertebrates genomes were enlarged relative to the basic invertebrate complement by one or two rounds of genome doubling, although subsequent work suggested that these events occurred on the vertebrate stem after divergence of the lancelet lineage 5,6 . Although the sequencing of the human and other vertebrate genomes has shown that the gene number in vertebrates is comparable to, or only modestly greater than, that of invertebrates 7,8 , evidence for large-scale segmental or whole-genome duplications on the vertebrate stem has mounted, with the parallel realization that most gene duplicates from such events are rapidly lost (reviewed in ref.…”

mentioning

confidence: 99%