Ap. Vogler et al., PHYLOGENETIC ANALYSIS OF SLIPPAGE-LIKE SEQUENCE VARIATION IN THE V4 RIBOSOMAL-RNA EXPANSION SEGMENT IN TIGER BEETLES (CICINDELIDAE), Molecular biology and evolution, 14(1), 1997, pp. 6-19
Sequence variation in the middle part of the small-subunit rRNA was st
udied for representatives of the major groups in the family Cicindelid
ae (Coleoptera). All taxa exhibited a much expanded segment in variabl
e region V4 compared to D. melanogaster. This expanded segment was not
found in other groups of beetles, including three taxa in the closely
related Carabidae. Secondary structure predictions indicate that the
expanded segment folds into a single stem-loop structure in all taxa.
Despite its structural conservation, the fragment differs strongly in
primary sequence, even between closely related sister taxa. Several fe
atures of these sequences are consistent with slippage replication as
the mechanism that has generated this sequence variation: the level of
internal sequence repetition as measured by the relative simplicity f
actor (RSF), its variation in length between close relatives, and the
strong nucleotide bias compared to the remainder of the gene. With few
exceptions, there was also a correlation between sequence length and
the level of sequence repetition, frequently interpreted as the result
of slippage. Phylogenies inferred from the expansion segment were not
consistent with existing hypotheses from other molecular data for the
group. This indicates that DNA sequences in this region are not homol
ogous throughout the entire Cicindelidae, but it leaves open the possi
bility that this expansion segment can be used for phylogeny reconstru
ction within subgroups. The implications of a phylogenetic approach to
the understanding of slippage-like evolution are discussed.