Pleiotropy, redundancy and the evolution of flowers.
Most angiosperm flowers are tightly integrated, functionally bisexual shoots that have carpels with enclosed ovules. Flowering plants evolved from within the gymnosperms, which lack this combination of innovations. Paradoxically, phylogenetic reconstructions suggest that the flowering plant lineage substantially pre-dates the evolution of flowers themselves. We provide a model based on known gene regulatory networks whereby positive selection on a single, partially redundant gene duplicate 'trapped' the ancestors of flower-bearing plants into the condensed, bisexual state approximately 130 million years ago. The LEAFY (LFY) gene of Arabidopsis encodes a master regulator that functions as the main conduit of environmental signals to the reproductive developmental program. We directly link the elimination of one LFY paralog, pleiotropically maintained in gymnosperms, to the sudden appearance of flowers in the fossil record.
Natural History Museums and Botanical Garden, University of Oslo, Sarś gate 1, N-0562 Oslo, Norway. victor.albert@nhm.uio.no
Victor A
VA
Albert
David G
DG
Oppenheimer
Charlotte
C
Lindqvist
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D032462:Cycadopsida / Q000145:classification / Q000235:genetics; D019143:Evolution, Molecular; D019684:Magnoliopsida / Q000145:classification / Q000235:genetics; D008954:Models, Biological; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D018547:Plant Stems / Q000235:genetics* / Q000254:growth & development; D014157:Transcription Factors
D029681:Arabidopsis Proteins; C074747:LFY protein, Arabidopsis; D010940:Plant Proteins; D014157:Transcription Factors