2.2 Genome survey
Genomic DNA was extracted from a single adult female of S.
peregrina using SDS method (Rinkevich et al. 2006). A library
with insert sizes of 400 bp was generated by Illumina TruSeq Nano DNA
Library Prep Kit and sequenced to 150-nt paired end reads (PE 150 bp) on
the Illumina HiSeq Xten (San Diego, CA, USA). After quality control,
low-quality reads, sequencing adapters, contaminated reads and ambiguous
bases were removed, whilst duplicates were filtered out. Finally, the
clean data were applied to enable the genome survey and calibrate
subsequent genomic assembly. Meanwhile, in order to estimate the genome
size and heterozygosity of S. peregrina , we performed theK -mer distribution (K = 17) using the Jellyfish program
(Marcais& Kingsford 2011).