Vol. 56, 2017
(update: 2017.4.17)
Loss and Gain of Group I Introns in the Mitochondrial
Cox1 Gene of the Scleractinia (Cnidaria; Anthozoa)
Yaoyang Chuang1,2, Marcelo Kitahara3,4,
Hironobu Fukami5, Dianne Tracey6, David J. Miller3,7,*,
and Chaolun Allen Chen1,2,*
doi:10.6620/ZS.2017.56-09
1Biodiversity Research Center, Academia Sinica,
Nankang, Taipei 115, Taiwan
2Institute of Oceanography, National Taiwan
University, Taipei 106, Taiwan
3School of Pharmacy and Molecular Sciences, James
Cook University, Townsville 4810, QLD, Australia
4Centro
de Biologia Marinha, Universidade de São Paulo Rodovia Manoel Hyppólito
do Rego, km 131,5 Praia do Cabelo Gordo 11600-000, Sao Sebastiao, SP,
Brazil
5Department of Marine Biology and Environmental
Science, University of Miyazaki, Miyazaki 889-2192, Japan
6National Institute of Water and Atmospheric
Research, Wellington 6021, New Zealand
7ARC Centre of Excellence for Coral Reef Studies,
James Cook University, Townsville 4810, QLD, Australia
8Taiwan International Graduate Program
(TIGP)-Biodiversity, Academia Sinica, Nankang, Taipei 115, Taiwan
(Received 19 January 2017; Accepted 12 April 2017)
Yaoyang Chuang, Marcelo Kitahara, Hironobu Fukami,
Dianne Tracey, David J. Miller, and
Chaolun Allen Chen (2017) Group
I introns encoding a homing endonuclease gene (HEG) that is potentially
capable of sponsoring mobility are present in the cytochrome oxidase
subunit 1 (cox1) gene of some Hexacorallia, including a number
of scleractinians assigned to the “robust” coral clade. In an effort to
infer the evolutionary history of this cox1 group I intron,
DNA sequences were determined for 12 representative “basal” and
“complex” corals and for 11 members of the Corallimorpharia, a sister
order of the Scleractinia. Comparisons of insertion sites, secondary
structures, and amino acid sequences of the HEG implied a common origin
for cox1 introns of corallimorpharians, and basal and
complex corals, but cox1
introns of robust corals were highly divergent, most likely reflecting
independent acquisition. Phylogenetic analyses with a calibrated
molecular clock suggested that cox1 introns of
scleractinians
and corallimorpharians have persisted at the same insertion site as
that in the common ancestor 552 million years ago (mya). This ancestral
intron was probably lost in complex corals around 213 mya in the
junction between the Permian and Triassic. The coral cox1 gene
remained intronless until new introns, probably from sponges or fungi,
reinvaded different positions of the cox1
gene in robust corals around 135 mya in the Cretaceous, and then it
subsequently began to lose them around 65.5 mya in some robust coral
lineages coincident with the later Maastrichtian extinction at the
Cretaceous-Tertiary boundary.
Key words: Group I
intron,Cytochrome oxidase I, Scleractinian, Corallimorpharian, Mass
extinction.
*Correspondence: Tel: 886-2-27899549. E-mail:
cac@gate.sinica.edu.tw (CA Chen); david.miller@jcu.edu.au (DJ Miller).
Citation: Chuang Y, Kitahara M, Fukami H, Tracey D,
Miller DJ, Chen CA. 2017. Loss and gain of group I introns in the
mitochondrial Cox1 gene of the Scleractinia (Cnidaria; Anthozoa). Zool Stud 56:9. doi:10.6620/ZS.2017.56-09.
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