TY - JOUR
T1 - Species boundaries and phylogenetic relationships within the green algal genus Codium (Bryopsidales) based on plastid DNA sequences
AU - Verbruggen, H.
AU - Leliaert, F.
AU - Maggs, Christine
AU - Shimada, S.
AU - Schils, T.
AU - Provan, Jim
AU - Booth, David
AU - Murphy, S.
AU - De Clerck, O.
AU - Littler, D.S.
AU - Littler, M.M.
AU - Coppejans, E.
PY - 2007/7
Y1 - 2007/7
N2 - Despite the potential model role of the green algal genus Codium for studies of marine speciation and evolution, there have been difficulties with species delimitation and a molecular phylogenetic framework was lacking. In the present study, 74 evolutionarily significant units (ESUs) are delimited using 227 rbcL exon 1 sequences obtained from specimens collected throughout the genus' range. Several morpho-species were shown to be poorly defined, with some clearly in need of lumping and others containing pseudo-cryptic diversity. A phylogenetic hypothesis of 72 Codium ESUs is inferred from rbcL exon 1 and rps3-rp/16 sequence data using a conventional nucleotide substitution model (GTR + Gamma + I), a codon position model and a covariotide (covarion) model, and the fit of a multitude of substitution models and alignment partitioning strategies to the sequence data is reported. Molecular clock tree rooting was carried out because out-group rooting was probably affected by phylogenetic bias. Several aspects of the evolution of morphological features of Codium are discussed and the inferred phylogenetic hypothesis is used as a framework to study the biogeography of the genus, both at a global scale and within the Indian Ocean. (c) 2007 Elsevier Inc. All rights reserved.
AB - Despite the potential model role of the green algal genus Codium for studies of marine speciation and evolution, there have been difficulties with species delimitation and a molecular phylogenetic framework was lacking. In the present study, 74 evolutionarily significant units (ESUs) are delimited using 227 rbcL exon 1 sequences obtained from specimens collected throughout the genus' range. Several morpho-species were shown to be poorly defined, with some clearly in need of lumping and others containing pseudo-cryptic diversity. A phylogenetic hypothesis of 72 Codium ESUs is inferred from rbcL exon 1 and rps3-rp/16 sequence data using a conventional nucleotide substitution model (GTR + Gamma + I), a codon position model and a covariotide (covarion) model, and the fit of a multitude of substitution models and alignment partitioning strategies to the sequence data is reported. Molecular clock tree rooting was carried out because out-group rooting was probably affected by phylogenetic bias. Several aspects of the evolution of morphological features of Codium are discussed and the inferred phylogenetic hypothesis is used as a framework to study the biogeography of the genus, both at a global scale and within the Indian Ocean. (c) 2007 Elsevier Inc. All rights reserved.
UR - http://www.scopus.com/inward/record.url?scp=34249666092&partnerID=8YFLogxK
U2 - 10.1016/j.ympev.2007.01.009
DO - 10.1016/j.ympev.2007.01.009
M3 - Article
VL - 44(1)
SP - 240
EP - 254
JO - Molecular Phylogenetics and Evolution
JF - Molecular Phylogenetics and Evolution
SN - 1055-7903
IS - 1
ER -