There are many more angelfish in the sea
Why do some species of fish form hybrids and others not? In an attempt to answer this question, new research has found that angelfish are the main hybridizers of coral reef fish.
Renowned magazine Royal Society procedure B. has a new fish on the front: the sea angelfish. It has more stellar power than any other group of coral reef fish due to a new study highlighting the remarkably high incidence and tendency for hybridization in this family (including between species).
Hybridization refers to the process by which two different species mate and produce hybrid offspring.
The research was led by Yi-Kai (Kai) Tea, a PhD student at the School of Life and Environmental Sciences, University of Sydney.
He and his colleagues, Professors Nathan Lo and Simon Ho, Dr. Joseph DiBattista from the Australian Museum, Jean-Paul Hobbs from the University of Queensland, and Federico Vitelli from Edith Cowan University wanted to find out why only some fish produce hybrids, the factors that make this easier.
After choosing to focus on “one of the most charismatic and well-known groups of coral reef fish,” the sea angelfish, they found that 42 species – almost half of all known species of sea angelfish – form hybrids.
“This is one of the most common cases of hybridization in coral reef fish,” said Tea.
Close opposites attract
“We also found that hybrids are often produced between angelfish species that are distantly related to each other. Some are separated from each other by more than 10 million years in the evolutionary period. ”
Other hybrids were found between species with a pairwise spacing of over 12 percent in mitochondria DNA. The pairwise spacing is a measure of the differences in pairs of DNA sequences.
“This genetic segregation is pretty amazing when you consider that hybrids are rarely reported between species that are more than 2 percent genetic apart,” Tea said. “Although coral reef fish hybrids are common; They are usually formed from closely related species. ”
Limitless hybridization
A third important finding was that angelfish hybridize wherever different species exist. This is in contrast to other coral reef fish, which tend to hybridize only within certain zones of their common habitats.
“When it comes to coral reef fish hybridization, much remains unanswered, especially when it comes to the why and the formation of hybrids. We still don’t know why some species hybridize and others don’t. For example the royal angelfish, Pygoplites diacanthusis found throughout the Indian and Pacific Oceans, but hybrids have never been reported for this species, ”Tea said.
“To unlock the secrets of hybridization in coral reefs, we have only just scratched the surface.”
Reference: “Angels in disguise: The sympatric hybridization in sea angelfish is widespread and occurs between very different lineages” by Yi-Kai Tea, Jean-Paul A. Hobbs, Federico Vitelli, Joseph D. DiBattista, Simon YW Ho and Nathan Lo. August 5, 2020, Royal Society procedure B..
DOI: 10.1098 / rspb.2020.1459
Y.-KT was funded by a grant from the Australian Government’s Research Training Program and a Postgraduate Award from the Australian Museum Research Institute. J.-PAH was funded by the Australian Research Council (Grant No. DE200101286). JDD was funded by an Early Career Research Fellowship from Curtin University. SYWH and NL were funded by the Australian Research Council (grant numbers FT160100167 and FT160100463, respectively).