Abstract Detail

Phylogenomics

Effects of taxon sampling and shifts in mode of organellar inheritance on Gymnosperm phylogeny.

Sampling for phylogenetic studies often must strike a balance between phylogenetic breadth, phylogenetic density, and genomic depth when choosing taxa to include in a study. Single taxa are often used as representatives for large, diverse taxonomic groups. There is a growing amount of public sequence data available via sources such as GenBank. This study synthesizes published plastid, mitochondrial, and nuclear data into an in-depth analysis of Gymnosperm phylogeny. The dataset has three main sources: 1) assembled whole plastid genomes; 2) genes sequenced using a targeted approach; and 3) raw high-throughput sequencing data from NCBI SRA (Sequence Read Archive). Phylogenetic analyses were conducted on different subsets of data to investigate the effects of breadth and density of taxon sampling on the overall gymnosperm phylogeny including the placement of groups with unstable phylogenetic resolution, such as the Gnetales.
Additionally, I investigated the effects of differing modes of organellar inheritance. While the nuclear genome is biparentally inherited, plants have two organellar genomes which are uniparentally inherited: plastid and mitochondrial. Mitochondrial genomes are almost universally maternally inherited. In Angiosperms, plastid genomes are generally maternally inherited as well, but several groups of Gymnosperms (notably Pinaceae) exhibit paternal plastid inheritance. Maternally inherited loci are dispersed by seeds, while paternally inherited loci migrate through both seeds and pollen. The dispersal ability of pollen is generally much greater than that of seeds. This difference in dispersal ability can have a significant effect on genetic differentiation. I investigate the potential effects of this phenomenon on phylogenetic signal and concordance among genetic compartments.

1 - New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458, USA

Keywords:
gymnosperm
organelle inheritance
taxon sampling
Pinaceae.

Presentation Type: Oral Paper
Number: PHYLO II006
Abstract ID:703
Candidate for Awards:None