Sammelbandbeitrag

Erschienen in: Developmental Genetics and Plant Evolution

Herausgeberliste: Cronk, Q; Bateman, R; Hawkins, J

Jahr der Veröffentlichung: 2002

Seiten: 173-205

ISBN: 9780415257916

Serientitel: Systematics Association Special Volumes

Abstract: 

Despite dramatic progress in the reconstruction of seed
plant phylogeny, understanding the evolutionary origin of flowers has remained
one of the most intractable problems of botany and evolutionary biology. Novel
attempts to solve the“abominable mystery” of flower origin are currently being
made by evolutionary developmental genetics. Since the structure of the flower
is sculpted by floral organ identity genes encoding MADS-domain transcription
factors, clarifying the evolution of these genes should in theory provide us
with valuable clues concerning flower origin. Current evidence suggests that
non-seed land plants such as ferns and mosses lack orthologs of floral organ
identity genes. In contrast, extant gymnosperms, beingthe sister group of the
angiosperms, have orthologs of genes that specify petal and stamen or stamen,
carpel and ovule identity in flowering plants (class B and class C and D floral
organ identity genes, respectively). In addition, the class B genes have a
recently identified sister group in both gymnosperms and angiosperms; these
Bsister genes are involved in the development of ovules and carpels. The presence
of orthologs of B, Bsister, and C and D genes in diverse gymnosperms and angiosperms
suggests that the genetic system for the specification of reproductive organ
identity in the angiosperm flower was recruited during evolution from an
ancestral and functionally related system, rather than being established de
novo. This system was already present in the last common ancestor of all extant
seed plants about 300million years ago and may have been involved in sex
determination and the specification of reproductive organs. At the molecular
genetic level, therefore, flower origin seems far less “abominable” than
morphology and paleontology had suggested for more than a century.

Harvard-Zitierstil: Theißen, G., Becker, A., Winter, K., Münster, T., Kirchner, C. and Saedler, H. (2002) How the land plants learned their floral ABCs: the role of MADS-box genes in the evolutionary origin of flowers, in Cronk, Q., Bateman, R. and Hawkins, J. (eds.) Developmental Genetics and Plant Evolution. London: CRC Press, pp. 173-205

APA-Zitierstil: Theißen, G., Becker, A., Winter, K., Münster, T., Kirchner, C., & Saedler, H. (2002). How the land plants learned their floral ABCs: the role of MADS-box genes in the evolutionary origin of flowers. In Cronk, Q., Bateman, R., & Hawkins, J. (Eds.), Developmental Genetics and Plant Evolution (pp. 173-205). CRC Press.