SMITH, JAMES F.1*, DAVID A. BAUM2, and LENA HILEMAN3. 1Dept. of Biology, Boise State University, 1910 University Drive, Boise, ID, 83725, USA; 2Dept. of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI, 53706, USA; 3Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA. - Evolution and phylogenetic analysis of Gcyc (a Gesneriaceae cycloidea homolog) in subfamily Gesnerioideae (Gesneriaceae).
The gene cycloidea (cyc) has been documented in its
control of bilateral floral symmetry in Antirrhinum and
Linaria. The role of cyc in the control of floral
symmetry in other genera and its phylogenetic potential have not been
widely explored. Recent work on subfamily Cyrtandroideae of
Gesneriaceae has revealed a cyc homolog named Gcyc. At
least two duplicates of this gene are known from Cyrtandroideae.
Phylogenetic analyses using these sequences at the intra- and
intergeneric levels have shown that Gcyc can provide data of
phylogenetic utility. Using primers designed to amplify Gcyc
from diverse Gesneriaceae, one copy of Gcyc from most taxa was
isolated. In order to amplify Gcyc from additional
(problematic) taxa, a new, internal 5' primer was designed. Sequences
were obtained from all tribes and many genera of Gesnerioideae
(including genera with non-bilateral floral symmetry). In only two
genera (Fieldia and Negria) have duplications of
Gcyc been found. Sequences are readily alignable and show less
variability than found in subfamily Cyrtandroideae on the basis of
indels. There is no evidence for frame shift or stop codon mutations,
implying that gene function is maintained across all taxa. Parsimony
and maximum likelihood are congruent with previous analyses of
relationships among tribes and genera in Gesnerioideae.
Key words: cycloidea, Gcyc, Gesneriaceae, Gesnerioideae, phylogeny