Abstract Detail

Discerning homologies: Gene expression, development, and morphology

Kellogg, Elizabeth [1], Malcomber, Simon [1].

Gene expression and organ identity in grasses.

Gene and genome duplications are important creative forces in evolution, providing the raw genetic material on which selection can act. Current theory suggests that duplicate genes should diverge in function, possibly by partitioning the ancestral expression domain (subfunctionalization). We show that MADS-box transcription factors are duplicated in the common ancestor of the grasses, and that the duplicates have indeed diverged in expression; from the divergent expression patterns we infer divergence in function. In particular, LEAFY HULL STERILE1 and its duplicate OsMADS5, both SEPALLATA-like genes have partly complementary expression patterns in the grasses. The expression pattern of each gene, however, differs from species to species. Structures that would, by any criterion, be considered homologous (e.g. stamens) do not express the same sets of genes. Our data combined with phenotypes of mutants suggest that identity of a floral organ may require SEP-like genes, but for at least some organs the precise gene involved may not matter. Gene expression alone is thus only one of several useful pieces of information about homology.

1 - University of Missouri-St. Louis, Biology, 8001 Natural Bridge Road, St. Louis, Missouri, 631321, USA

Keywords:
ABC model
developmental genetics
duplicate genes
floral evolution
gene expression
grasses
MADS-box genes
Poaceae.

Presentation Type: Symposium
Session: 14-6
Location: Ballroom 1 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 3:15 PM
Abstract ID:543