Genetic Diversity, Biogeography, and Evolution of Apomixis in North American Arabis holboelli Hornem. and Arabis drummondii Gray (Brassicaceae).
Abstract
Apomixis, the production of seeds by vegetative means, is a trait that has 'greatly attracted the interest of numerous botanists since decades. -It is widely distributed among flowering plants and the responsible genetic background might involve only one or a few genes. The agronomical importance of this trait is enormous, because of the greatly enhanced possibilities to propagate seed material, but also to open a new way to produce seeds with missing or greatly reduced geneflow between individuals, which might even help to solve problems of introgression of genes from genetically manipulated plants into wildtype individuals. Among dicots apomixis has been analyzed mostly on a descriptional level, and less attention has been paid on the evolution of this trait. Among the family of Brassicaceae the dicot model plant for molecular biologists, Arabidopsis thaliana, do not show this trait, and, therefore, one could not use the enormous molecular knowledge from this plant to analyze the. genetic background in this species directly. However, among North American Arabis species apomixis is widespread and has been described to occur even on the diploid level. North American Arabis consists of more than 50 species depending on the underlying species concept. More than 10% of these taxa are known only as triploids and apomixis is the assumed way of seed production. Additional 20% are known as diploids as well as triploids, which might indicate varying breeding systems within a single taxon. Therefore, apomixis played a major role as a mechanism of population differentiation and speciation within North American Arabis. In this project the genetic diversity of Arabis holboelfii and closely related Arabis drummondii should be analyzed on the molecular level. The degree of apomixis within a population has greater impact on the distribution of its total genetic variation. Therefore, populational genetic diversity and the intra-populational degree of apomixis should be analyzed using molecular markers and cytological investigations. Genetic variation on the populational level should be used to estimate inter populational genetic distances and to infer a phylogenetic network of Arabis populations. Analyses of correlations between geographic distribution of molecular variation, apomixis and genetic distances between populations should help to answer principial questions of phytobiogeography and evolution of Arabis holboellii and Arabis drummondii in the light of apomixis.
keywords apomixis population genetics Arabis systematics evolution
Publikationen
Multiple hybrid formation in natural populations: concerted evolution of the internal transcribed spacer of nuclear ribosomal DNA (ITS) in North American Arabis divaricarpa (Brassicaceae).
Autoren: Koch, MA; Dobes, C; Mitchell-Olds, T; Jahr: 2003
Journal articles
Genetic diversity, biogeography, and evolution of apomixis in North American Arabis holhoellii Hornrm. and Arabis drummondii Gray (Brassicaceae)
Autoren: Dobe¿, Ch. Jahr: 2003
Doctoral Thesis
Project staff
Marcus Koch
Ao.Univ.Prof. Dipl.-Biol. Dr.rer.nat. Marcus Koch
Project Leader
01.08.2000 - 31.03.2003
BOKU partners
External partners
Max Planck Institute for Chemical Ecology, Jena
none
partner