Genetics of cryptic speciation within an Arctic mustard, Draba nivalis

PLoS One. 2014 Apr 1;9(4):e93834. doi: 10.1371/journal.pone.0093834. eCollection 2014.

Abstract

Crossing experiments indicate that hybrid sterility barriers frequently have developed within diploid, circumpolar plant species of the genus Draba. To gain insight into the rapid evolution of postzygotic reproductive isolation in this system, we augmented the linkage map of one of these species, D. nivalis, and searched for quantitative trait loci (QTLs) associated with reproductive isolation. The map adds 63 new dominant markers to a previously published dataset of 31 co-dominant microsatellites. These markers include 52 amplified fragment length polymorphisms (AFLPs) and 11 sequence-specific amplified polymorphisms (SSAPs) based on retrotransposon sequence. 22 markers displaying transmission ratio distortion were further included in the map. We resolved eight linkage groups with a total map length of 894 cM. Significant genotype-trait associations, or quantitative trait loci (QTL), were detected for reproductive phenotypes including pollen fertility (4 QTLs), seed set (3 QTLs), flowering time (3 QTLs) and number of flowers (4 QTLs). Observed patterns of inheritance were consistent with the influence of both nuclear-nuclear interactions and chromosomal changes on these traits. All seed set QTLs and one pollen fertility QTL displayed underdominant effects suggestive of the involvement of chromosomal rearrangements in hybrid sterility. Interestingly, D. nivalis is predominantly self-fertilizing, which may facilitate the establishment of underdominant loci and contribute to reproductive isolation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amplified Fragment Length Polymorphism Analysis
  • Arctic Regions
  • Chromosome Mapping
  • Fertility / genetics
  • Flowers / genetics
  • Genetic Speciation*
  • Microsatellite Repeats / genetics
  • Mustard Plant / genetics*
  • Mustard Plant / growth & development
  • Pollen / genetics
  • Quantitative Trait Loci / genetics*
  • Reproductive Isolation*
  • Seeds / genetics

Grants and funding

Funding was obtained from the Natural History Museum, University of Oslo and the Swiss National Science Foundation (grants PBLAA122735 and PZ00P3-131950 to CP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.