Molecular Phylogeny of Grey Mullets Based on Mitochondrial DNA Sequence Analysis: Evidence of a Differential Rate of Evolution at the Intrafamily Level

Molecular Phylogeny of Grey Mullets (Teleostei: Mugilidae) in Greece: Evidence from Sequence Analysis of mtDNA Segments

“…This could be the result of the faster substitution rate observed in this species, and it could be explained as a combined effect of nucleotide bias (especially on the third codon position of CO I) and saturation of signal (Martin 1995). This observation is in agreement with previous studies by our group (Papasotiropoulos et al 2001(Papasotiropoulos et al , 2002 using allozyme and PCR-RFLP analysis, as well as with the studies performed by Caldara et al (1996), Murgia et al (2002), Rossi et al (2004), andTuran et al (2005), among others, supporting the hypothesis that M. cephalus is the most genetically distinct species belonging to a different lineage that excludes the genera Liza and Chelon. This hypothesis is also supported by chromosome studies by Cataudella et al (1974) and more recently by Rossi et al (1997) and Gornung et al (2001), who stated that the M. cephalus karyotype is considered closest to the karyotype described by Ohno (1974) as ancestral for all teleosts.…”

“…This was not supported by our previous study (Papasotiropoulos et al 2001) or by Autem and Bonhomme (1980) based on allozymic data. Other studies, however, based on mtDNA and allozyme data (e.g., Caldara et al 1996;Rossi et al 2004;Turan et al 2005) seem to agree with our current findings, leaving room for reconsidering the modern systematic classification of those species.…”

“…The lack of parallel evolution between morphology and some portions of DNA has already been reported for other groups of fish (e.g., Meyer et al 1990) and might be explained by differences in the selective constraints operating on these two characters (Caldara et al 1996). At the same time, we did not detect any appreciable degree of genetic differentiation between Liza and Chelon species.…”

“…Those different approaches agree to some extent, especially regarding the position of M. cephalus with respect to the other species, but there are important issues that need further clarification. Studies based on allozyme electrophoresis of Mediterranean mullets (Autem and Bonhomme 1980;Papasotiropoulos et al 2001;Rossi et al 2004;Turan et al 2005) provided conflicting results not only among themselves but also compared with other studies based on mtDNA data (Caldara et al 1996;Papasotiropoulos et al 2002;Murgia et al 2002;Rossi et al 2004). The major issue concerns the phylogenetic relationships among the Liza species and particularly the existence of a common Liza-Chelon clade, which if proven will bring into question the monophyletic origin of the genus Liza.…”

Mitochondrial DNA diversity in Atherina boyeri populations as determined by RFLP analysis of three mtDNA segments

“…Large genetic divergence, at least for some portions of DNA, has already been reported for other groups of fish that have fairly similar morphology (Meyer et al, 1990;Sturmbauer and Meyer, 1992;Patarnello et al, 1994;Papasotiropoulos et al, 2002). This situation could be explained by differences in the selective constraints operating on these two general characters, which seems to lead to the lack of parallel evolution of these characters (Caldara et al, 1996;Rossi et al, 1998).…”