Transcriptome Sequencing and Assembly: Greenland Samples
Total RNA was extracted from the kidney and muscle employing the
mirVanaTM RNA extraction kit (Ambion). RNA integrity of the individual RNA
samples was assessed on a 1% agarose gel using an Agilent 2100 Bioanalyzer
(Agilent Technologies). Library preparation was performed using the
ScriptSeqTM mRNA-seq library preparation kit from Epicenter according to
the manufacturer’s protocol (Epicenter) and sequenced (100 bp paired end)
as multiplexed samples using the Illumina HiSeq 2000 analyzer. Fastq generation
and demultiplexing were performed using the CASAVA 1.8.2 package
(Illumina). The fastq files were filtered for adapters, quality, and length using
Trimmomatic (v.0.27), with a window size of 4, a base quality cutoff of 20,
and a minimum length of 60 (Lohse et al., 2012). De novo transcriptome assembly
was performed using the short read assembler software Trinity (release
2013-02-25), which is based on the de Bruijn graph method for assembly, with
default settings (Grabherr et al., 2011).