Abstract Detail

Phylogenomics

Zimmer, Elizabeth [1], Taylor, W. Carl [2], Schafran, Peter [3], Johnson, Gabriel [4].

DNA sequences identify cryptic species of quillworts (Isoetes L.).

The tetraploid Louisiana quillwort, Isoetes louisianensis, a rare plant found in St. Tammany and Washington Parishes, was placed on the Endangered Species List in 1992. Subsequently, several populations found in Mississippi also have been identified as Isoetes louisianensis. In order to test whether the Mississippi populations indeed are Isoetes louisianensis, DNA from the type locality and three of the Mississippi sites was extracted, amplified, cloned and sequenced for the nuclear intron 2 of the LEAFY gene that previously has been proven useful in resolving relationships across Isoetes. Sequences of basic diploids that were suspected of contributing a parental genome to the allotetraploids were obtained by direct Sanger sequencing. Together the sequences produced an evolutionary tree indicating that a single Mississippi population, from a "Gator Branch" site, possessed the same diploid parental genomes as the type species Isoetes louisianensis. In the case of the other two populations, from "Oakey Branch" and "Moody Branch" sites, different combinations of diploids were observed. Next Generation DNA Sequencing performed on the Illumina MiSeq instrument then produced complete chloroplast genomes for the four tetraploids and the three relevant diploid progenitor species previously obtained by LEAFY gene sequencing. Phylogenetic analyses of the sequences for the seven Isoetes plastomes identified the chloroplast donor (presumed maternal) genome of the tetraploids. Again, the "Gator Branch "population was most similar to the Isoetes louisianensis type species.

1 - Smithsonian Institution, National Museum of Natural History, Department of Botany, PO Box 37012, Washington, DC, 20013-7012
2 - Smithsonian Institution, Department of Botany, National Museum of Natural History, Washington, DC, 20013, USA
3 - Department Of Biological Sciences, Old Dominion University, Norfolk, VA, 23529-0266, USA
4 - Smithsonian Institution, Botany, P.O. Box 7012, NMNH, MRC 166, Washington, D.C., 20013

Keywords:
Isoetes
tetraploids
low-copy nuclear markers
Chloroplast Genome
Next generation sequencing.

Presentation Type: Oral Paper
Session: 1, Phylogenomics I
Location: 101/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 9:15 AM
Number: 1006
Abstract ID:220
Candidate for Awards:None