Genome size and karyotype evolution in the slipper orchids (Cypripedioideae: Orchidaceae)

Autor:	Antony V. Cox, Michael D. Bennett, Ilia J. Leitch, Gregory J. Abdelnour
Rok vydání:	1998
Předmět:	Genetics Cypripedium Context (language use) Plant Science Biology biology.organism_classification Genome Phragmipedium Cypripedioideae Paphiopedilum Evolutionary biology Molecular phylogenetics Genome size Ecology Evolution Behavior and Systematics
Zdroj:	American Journal of Botany. 85:681-687
ISSN:	0002-9122
DOI:	10.2307/2446538
Popis:	Nuclear DNA contents (4C) were estimated by Feulgen microdensitometry in 27 species of slipper orchids. These data and recent information concerning the molecular systematics of Cypripedioideae allow an interesting re-evaluation of karyotype and genome size variation among slipper orchids in a phylogenetic context. DNA amounts differed 5.7-fold, from 24.4 pg in Phragmipedium longifoliumto 138.1 pg in Paphiopedilum wardii.The most derived clades of the conduplicate-leaved slipper orchids have undergone a radical process of genome fragmentation that is most parsimoniously explained by Robertsonian changes involving centric fission. This process seems to have occurred independently of genome size variation. However, it may reflect environmental or selective pressures favoring higher numbers of linkage groups in the karyotype.
Databáze:	OpenAIRE
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