Reticulate evolution in diploid and tetraploid species of Polystachya (Orchidaceae) as shown by plastid DNA sequences and low-copy nuclear genes.

ABSTRACT:

Background and aims

Here evidence for reticulation in the pantropical orchid genus Polystachya is presented, using gene trees from five nuclear and plastid DNA data sets, first among only diploid samples (homoploid hybridization) and then with the inclusion of cloned tetraploid sequences (allopolyploids). Two groups of tetraploids are compared with respect to their origins and phylogenetic relationships.

Methods

Sequences from plastid regions, three low-copy nuclear genes and ITS nuclear ribosomal DNA were analysed for 56 diploid and 17 tetraploid accessions using maximum parsimony and Bayesian inference. Reticulation was inferred from incongruence between gene trees using supernetwork and consensus network analyses and from cloning and sequencing duplicated loci in tetraplo

SUBMITTER: Russell A 

PROVIDER: S-EPMC2889800 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature