Cryptic Speciation in Arctic Plants (completed)

Fieldwork in Alaska, summer 2009

Recent crossing experiments have shown that individuals within three diploid, circumpolar species of Draba (Brassicaceae) were mostly intersterile, suggesting that the formation of cryptic biological species may be common within arctic plants. The aim of my PhD is to gather insights about patterns and processes underlying speciation in the Arctic. Intraspecific crosses within various diploid species collected from Alaska, Svalbard and mainland Norway will be performed. Analysing the fertility of resulting hybrids will enable us to draw conclusions about the generality of sibling species formation in the Arctic. Comparing patterns of selfers vs. outcrossers will also give insights about the underlying evolutionary forces (drift vs. selection), expecting selfing to facilitate the accumulation of hybrid incompatibilities through genetic drift. We also aim at unravelling the precise molecular mechanisms underlying reproductive barriers in Draba nivalis. QTL analyses will be made on F2 hybrids from reciprocal crosses by associating fertility traits, such as seed set and pollen fertility, with a wide range of molecular markers (“Brassicaceae Building Block” markers, microsatellites, AFLP and SSAP). This will unravel to what extent chromosomal rearrangements, nuclear-nuclear and cytonuclear incompatibilities contribute to the rise of these intrinsic reproductive barriers and will allow us to characterize putative speciation loci.

Fieldwork was conducted during summer 2009 in Alaska, Canada, Svalbard and mainland Norway where a total of 20 species was collected. The first crossing experiments have already been conducted and preliminary results are expected in early 2011. 

Dryas octopetala
Silene acaulis
Cochlearia groenlandica
Ranunculus pygmaeus

Below is a list of plant species collected, and
included in the first crossing experiments:

Cardamine bellidifolia (Brassicaceae)

Cochlearia groenlandica (Brassicaceae)

Minuartia biflora (Caryophyllaceae)

Minuartia rubella (Caryophyllaceae)

Silene acaulis (Caryophyllaceae)

Silene uralensis (Caryophyllaceae)

Arctostaphylos alpinus (Ericaceae)

Loiseleuria procumbens (Ericaceae)

Cassiope tetragona (Ericaceae)

Polemonium boreale (Polemoniaceae)

Dryas octopetala (Rosaceae)

Sibbaldia procumbens (Rosaceae)

Ranunculus pygmaeus (Ranunculaceae)

Thalictrum alpinum (Ranunculaceae)

Saxifraga hyperborea (Saxifragaceae)

Saxifraga oppositifolia (Saxifragaceae)

Published Nov. 20, 2014 10:12 AM - Last modified Oct. 5, 2015 11:17 AM