Journalartikel

Jahr der Veröffentlichung: 1999

Seiten: 7342-7347

Zeitschrift: Proceedings of the National Academy of Sciences

Bandnummer: 96

Heftnummer: 12

ISSN: 0027-8424

eISSN: 1091-6490

DOI Link: https://doi.org/10.1073/pnas.96.13.7342

Verlag: National Academy of Sciences

Abstract: 

The evolutionary origin of the angiosperms (flowering plants sensu stricto)
is still enigmatic. Answers to the question of angiosperm origins are
intimately connected to the identification of their sister group among
extinct and extant taxa. Most phylogenetic analyses based on
morphological data agree that among the groups of extant seed plants,
the gnetophytes are the sister group of the angiosperms. According to
this view, angiosperms and gnetophytes are the only extant members of a
clade called “anthophytes” to emphasize their shared possession of
flower-like reproductive structures. However, most phylogeny
reconstructions based on molecular data so far did not support an
anthophyte clade, but also could not clarify the case because support
for alternative groupings has been weak or controversial. We have
isolated 13 different homologs of MADS-type floral homeotic genes from
the gnetophyte Gnetum gnemon. Five of these genes fall into
monophyletic gene clades also comprising putatively orthologous genes
from flowering plants and conifers, among them orthologs of floral
homeotic B and C function genes. Within these clades the Gnetum
genes always form distinct subclades together with the respective
conifer genes, to the exclusion of the angiosperm genes. This provides
strong molecular evidence for a sister-group relationship between
gnetophytes and conifers, which is in contradiction to widely accepted
interpretations of morphological data for almost a century. Our
phylogeny reconstructions and the outcome of expression studies suggest
that complex features such as flower-like reproductive structures and
double-fertilization arose independently in gnetophytes and angiosperms.

Harvard-Zitierstil: Winter, K., Becker, A., Münster, T., Kim, J., Saedler, H. and Theissen, G. (1999) MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants, Proceedings of the National Academy of Sciences, 96(12), pp. 7342-7347. https://doi.org/10.1073/pnas.96.13.7342

APA-Zitierstil: Winter, K., Becker, A., Münster, T., Kim, J., Saedler, H., & Theissen, G. (1999). MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants. Proceedings of the National Academy of Sciences. 96(12), 7342-7347. https://doi.org/10.1073/pnas.96.13.7342