AFLPs resolve phylogeny and reveal mitochondrial introgression within a species flock of African electric fish (Mormyroidea: Teleostei).
Estimating species phylogeny from a single gene tree can be especially problematic for studies of species flocks in which diversification has been rapid. Here we compare a phylogenetic hypothesis derived from cytochrome b (cyt b) sequences with another based on amplified fragment length polymorphisms (AFLP) for 60 specimens of a monophyletic riverine species flock of mormyrid electric fishes collected in Gabon, west-central Africa. We analyze the aligned cyt b sequences by Wagner parsimony and AFLP data generated from 10 primer combinations using neighbor-joining from a Nei-Li distance matrix, Wagner parsimony, and Dollo parsimony. The different analysis methods yield AFLP tree topologies with few conflicting nodes. Recovered basal relationships in the group are similar between cyt b and AFLP analyses, but differ substantially at many of the more derived nodes. More of the clades recovered with the AFLP characters are consistent with the morphological characters used to designate operational taxonomic units in this group. These results support our hypothesis that the mitochondrial gene tree differs from the overall species phylogeny due at least in part to mitochondrial introgession among lineages. Mapping the two forms of electric organ found in this group onto the AFLP tree suggests that posteriorly innervated electrocytes with nonpenetrating stalks have independently evolved from anteriorly innervated, penetrating-stalk electrocytes at least three times.
Sullivan
John P
JP
Department of Neurobiology and Behavior, W263 Seeley G. Mudd Hall, Cornell University, Ithaca, New York 14853, USA. js151@cornell.edu
Lavoué
Sébastien
S
Arnegard
Matthew E
ME
Hopkins
Carl D
CD
D000819:Animal Communication; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D045303:Cytochromes b / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004555:Electric Fish / Q000235:genetics*; D004557:Electric Organ / Q000033:anatomy & histology / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005681:Gabon; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D045483:Rivers; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial; D045303:Cytochromes b