Abstract Detail

Genetics Section

Clarkson, James J. [1], Kelly, Laura [2], Leitch, Andrew R. [3], Knapp, Sandra [4], Chase, Mark W. [2].

The dynamic Nicotiana genome: diploid hybrids, tetraploid hybrids and inter-allelic recombination.

The genus Nicotiana contains 75 species, approximately half of which are diploid and half are allotetraploid. We sequenced multiple plastid regions and used a phylogenetic approach to determine the maternal progenitors of the allotetraploids. The single copy nuclear gene glutamine synthetase (ncpGS), which is bi-parentally inherited, enabled us to determine the paternal progenitors. Discordance between these two datasets for certain diploid species have indicated the possibility of diploid (homoploid) hybrids within the genus. These data led us to re-examine the morphological characters of putative hybrid species, and we found, for example, that N. glutinosa has many floral characters similar to its paternal progenitor and habit and other vegetative traits more similar to its maternal parent. Further evidence of the homoploid hybrid origin of species comes from computer analyses, which have identified intragenic recombination between putative progenitor alleles. We are able to partition the ncpGS gene at the break points and construct phylogenetic trees that indicate the likely origin of different fragments.

Broader Impacts:

1 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, United Kingdom
2 - Royal Botanic Gardens Kew, Jodrell Laboratory, Richmond, Surrey, TW9 3AB, UK
3 - Queen Mary University of London, School of Biological Sciences, London, E1 4NS, United Kingdom
4 - Natural History Museum, Department of Botany, Cromwell Road, London, SW7 5BD, England

Keywords:
Nicotiana
polyploidy
Glutamine synthetase
low-copy nuclear gene
recombination
homoploid hybridization.

Presentation Type: Oral Paper:Papers for Sections
Session: 22
Location: 553B/Convention Center
Date: Monday, August 2nd, 2010
Time: 4:15 PM
Number: 22003
Abstract ID:305