title: The genetic basis for natural variation in heteroblasty in Antirrhinum.
abstract: Heteroblasty refers to the changes in leaf shape and size (allometry) along stems. Although evolutionary changes involving heteroblasty might contribute to leaf diversity, little is known of the extent to which heteroblasty differs between species or how it might relate to other aspects of allometry or other developmental transitions. Here, we develop a computational model that can quantify differences in leaf allometry between Antirrhinum (snapdragon) species, including variation in heteroblasty. It allows the underlying genes to be mapped in inter-species hybrids, and their effects to be studied in similar genetic backgrounds. Heteroblasty correlates with overall variation in leaf allometry, so species with smaller, rounder leaves produce their largest leaves earlier in development. This involves genes that affect both characters together and is exaggerated by additional genes with multiplicative effects on leaf size. A further heteroblasty gene also alters leaf spacing, but none affect other developmental transitions, including flowering. We suggest that differences in heteroblasty have co-evolved with overall leaf shape and size in Antirrhinum because these characters are constrained by common underlying genes. By contrast, heteroblasty is not correlated with other developmental transitions, with the exception of internode length, suggesting independent genetic control and evolution.
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.|Center for Biodiversity, Functional & Integrative Genomics, Department of Biology, University of Minho, 4710-057, Braga, Portugal.
authors.forename: M Manuela R
authors.initials: MMR
authors.lastname: Costa
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.
authors.forename: Suxin
authors.initials: S
authors.lastname: Yang
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Critchley
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.
authors.forename: Xianzhong
authors.initials: X
authors.lastname: Feng
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.
authors.forename: Yvette
authors.initials: Y
authors.lastname: Wilson
authors.affiliation: Department of Cell & Developmental Biology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Langlade
authors.affiliation: Department of Cell & Developmental Biology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK.
authors.forename: Lucy
authors.initials: L
authors.lastname: Copsey
authors.affiliation: Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JH, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hudson
mesh_terms: D032161:Antirrhinum / Q000235:genetics*; D005075:Biological Evolution; D002678:Chimera; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D008954:Models, Biological; D008957:Models, Genetic; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development; D040641:Quantitative Trait Loci