GAI homologues in the Hawaiian silversword alliance (Asteraceae-Madiinae)

Molecular evolution of growth regulators in a rapidly diversifying plant lineage

David L. Remington, Michael D. Purugganan

Research output: Contribution to journalArticle

Abstract

Accelerated evolution of regulatory genes has been proposed as an explanation for decoupled rates of morphological and molecular evolution. The Hawaiian silversword alliance (Asteraceae-Madiinae) has evolved drastic differences in growth form, including rosette plants, cushion plants, shrubs, and trees, since its origin ∼6 MYA. We have isolated genes in the DELLA subfamily of putative growth regulators from 13 taxa of Hawaiian and North American Madiinae. The Hawaiian taxa contain two copies of DaGAI that form separate clades within the Madiinae, consistent with an allotetraploid origin for the silversword alliance. DoGAl retains conserved features that have previously been identified in DELLA genes. Selective constraint in the Hawaiian DoGAl copies remains strong in spite of rapid growth form divergence in the silversword alliance, although the constraint was somewhat relaxed in the Hawaiian copies relative to the North American lineages. We failed to detect evidence for positive selection on individual codons. Notably, selective constraint remained especially strong in the gibberellin-responsive DELLA region for which the gene subfamily is named, which is truncated or deleted in all identified dwarf mutants in GAI homologues in different angiosperm species. In contrast with the coding region, however, ∼900 bp of the upstream flanking region shows variable rates and pattems of evolution, which might reflect positive selection on regulatory regions.

Original languageEnglish (US)
Pages (from-to)1563-1574
Number of pages12
JournalMolecular Biology and Evolution
Volume19
Issue number9
StatePublished - Sep 1 2002

Fingerprint

Argyroxiphium
Asteraceae
growth regulator
Molecular Evolution
growth regulators
Genes
gene
growth form
Growth
Gibberellins
Angiosperms
genes
Nucleic Acid Regulatory Sequences
Regulator Genes
regulator genes
codons
Codon
gibberellins
Angiospermae
shrubs

Keywords

  • Adaptive radiation
  • GAI
  • Madiinae
  • Regulatory genes
  • Selection
  • Silversword alliance

ASJC Scopus subject areas

  • Genetics
  • Biochemistry
  • Genetics(clinical)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Ecology, Evolution, Behavior and Systematics
  • Agricultural and Biological Sciences (miscellaneous)
  • Molecular Biology

Cite this

@article{2f90bc4b1bf44559bb7922a4e762d9f8,
title = "GAI homologues in the Hawaiian silversword alliance (Asteraceae-Madiinae): Molecular evolution of growth regulators in a rapidly diversifying plant lineage",
abstract = "Accelerated evolution of regulatory genes has been proposed as an explanation for decoupled rates of morphological and molecular evolution. The Hawaiian silversword alliance (Asteraceae-Madiinae) has evolved drastic differences in growth form, including rosette plants, cushion plants, shrubs, and trees, since its origin ∼6 MYA. We have isolated genes in the DELLA subfamily of putative growth regulators from 13 taxa of Hawaiian and North American Madiinae. The Hawaiian taxa contain two copies of DaGAI that form separate clades within the Madiinae, consistent with an allotetraploid origin for the silversword alliance. DoGAl retains conserved features that have previously been identified in DELLA genes. Selective constraint in the Hawaiian DoGAl copies remains strong in spite of rapid growth form divergence in the silversword alliance, although the constraint was somewhat relaxed in the Hawaiian copies relative to the North American lineages. We failed to detect evidence for positive selection on individual codons. Notably, selective constraint remained especially strong in the gibberellin-responsive DELLA region for which the gene subfamily is named, which is truncated or deleted in all identified dwarf mutants in GAI homologues in different angiosperm species. In contrast with the coding region, however, ∼900 bp of the upstream flanking region shows variable rates and pattems of evolution, which might reflect positive selection on regulatory regions.",
keywords = "Adaptive radiation, GAI, Madiinae, Regulatory genes, Selection, Silversword alliance",
author = "Remington, {David L.} and Purugganan, {Michael D.}",
year = "2002",
month = "9",
day = "1",
language = "English (US)",
volume = "19",
pages = "1563--1574",
journal = "Molecular Biology and Evolution",
issn = "0737-4038",
publisher = "Oxford University Press",
number = "9",

}

TY - JOUR

T1 - GAI homologues in the Hawaiian silversword alliance (Asteraceae-Madiinae)

T2 - Molecular evolution of growth regulators in a rapidly diversifying plant lineage

AU - Remington, David L.

AU - Purugganan, Michael D.

PY - 2002/9/1

Y1 - 2002/9/1

N2 - Accelerated evolution of regulatory genes has been proposed as an explanation for decoupled rates of morphological and molecular evolution. The Hawaiian silversword alliance (Asteraceae-Madiinae) has evolved drastic differences in growth form, including rosette plants, cushion plants, shrubs, and trees, since its origin ∼6 MYA. We have isolated genes in the DELLA subfamily of putative growth regulators from 13 taxa of Hawaiian and North American Madiinae. The Hawaiian taxa contain two copies of DaGAI that form separate clades within the Madiinae, consistent with an allotetraploid origin for the silversword alliance. DoGAl retains conserved features that have previously been identified in DELLA genes. Selective constraint in the Hawaiian DoGAl copies remains strong in spite of rapid growth form divergence in the silversword alliance, although the constraint was somewhat relaxed in the Hawaiian copies relative to the North American lineages. We failed to detect evidence for positive selection on individual codons. Notably, selective constraint remained especially strong in the gibberellin-responsive DELLA region for which the gene subfamily is named, which is truncated or deleted in all identified dwarf mutants in GAI homologues in different angiosperm species. In contrast with the coding region, however, ∼900 bp of the upstream flanking region shows variable rates and pattems of evolution, which might reflect positive selection on regulatory regions.

AB - Accelerated evolution of regulatory genes has been proposed as an explanation for decoupled rates of morphological and molecular evolution. The Hawaiian silversword alliance (Asteraceae-Madiinae) has evolved drastic differences in growth form, including rosette plants, cushion plants, shrubs, and trees, since its origin ∼6 MYA. We have isolated genes in the DELLA subfamily of putative growth regulators from 13 taxa of Hawaiian and North American Madiinae. The Hawaiian taxa contain two copies of DaGAI that form separate clades within the Madiinae, consistent with an allotetraploid origin for the silversword alliance. DoGAl retains conserved features that have previously been identified in DELLA genes. Selective constraint in the Hawaiian DoGAl copies remains strong in spite of rapid growth form divergence in the silversword alliance, although the constraint was somewhat relaxed in the Hawaiian copies relative to the North American lineages. We failed to detect evidence for positive selection on individual codons. Notably, selective constraint remained especially strong in the gibberellin-responsive DELLA region for which the gene subfamily is named, which is truncated or deleted in all identified dwarf mutants in GAI homologues in different angiosperm species. In contrast with the coding region, however, ∼900 bp of the upstream flanking region shows variable rates and pattems of evolution, which might reflect positive selection on regulatory regions.

KW - Adaptive radiation

KW - GAI

KW - Madiinae

KW - Regulatory genes

KW - Selection

KW - Silversword alliance

UR - http://www.scopus.com/inward/record.url?scp=0036727870&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036727870&partnerID=8YFLogxK

M3 - Article

VL - 19

SP - 1563

EP - 1574

JO - Molecular Biology and Evolution

JF - Molecular Biology and Evolution

SN - 0737-4038

IS - 9

ER -