Abstract Detail

Population Genetics/Genomics

Suissa, Jacob [1], Taylor, W. Carl [2], Kinosian, Sylvia [3], Schafran, Peter [4], Bolin, Jay [5], Zimmer, Elizabeth [6].

Revealing the origins of a polyploid complex of Isoëtes in northwestern North America.

Polyploidy and hybridization are known to be important processes in the evolution of seedless vascular plants. Compared to spermatophytes, ferns and lycophytes have fewer reproductive barriers which encourages the formation of reticulate species complexes. As such, there is a large body of research on reticulation in these groups, but much of this work has focused on homosporous ferns. Far fewer studies have focused on these dynamics in heterosporous lycophytes. One such group is the aquatic lycophyte genus Isoëtes, which has long been a recalcitrant clade for systematists. Extreme morphological conservation, recent radiations, high ploidy levels, and frequent hybridization have challenged traditional approaches (i.e., morphometrics and single-gene sequencing) to reveal the complicated evolutionary history of Isoëtes. Next-generation sequencing approaches such as restriction site associated DNA sequencing (RADseq) have helped illuminate relationships in reticulate complexes of homosporous ferns and seem promising for difficult groups such as Isoëtes. Here, we present the first study of a reticulate species complex of Isoëtes using RADseq data coupled with data from chloroplast (plastid) genomes and low copy nuclear genes. We estimate a plastid and nuclear phylogeny and assess the population structure of a reticulate species complex of Isoëtes from northwestern North America. Our data illuminate the evolutionary history of these taxa and support some of the previously hypothesized hybridization events, as well as provide novel evidence for backcrossing between hybrids and their progenitors.

1 - Harvard University, 1300 Centre St, 1300 Centre St, Boston, MA, 02131, United States
2 - 2912 22nd St N, 2912 22nd St N, Arlington, VA, 22201, United States
3 - Utah State University, Biology, 5305 Old Main Hill, Logan, Utah, 84322, United States
4 - Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY, 14853, US
5 - Catawba College, 2300 W Innes St., Salisbury, NC, 28144, United States
6 - Smithsonian NMNH, Botany MRC 166, P.O. Box 37102, Smithsonian National Museum Of Natural History, Washington, DC, 20013, United States

Keywords:
RADSeq
allopolyploidy
reticulate evolution
lycophytes.

Presentation Type: Oral Paper
Session: POPGEN3, Population Genetics/Genomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:15 AM
Number: POPGEN3002
Abstract ID:804
Candidate for Awards:Margaret Menzel Award