Whose genome has been sequenced? Nasuia deltocephalinicola

de-novo-sequencingThe human genome comprises more than 3 billion base pairs and builts up more than 20,000 protein coding genes. For genomes like this high-throughput sequencers, like the HiSeq 2000 are a revelation. In this article we talk about the smallest genome sequenced so far – here sequencing with the MiSeq is more than sufficient. The main role of this small symbiont (Nasuia deltocephalinicola) together with the symbiont Sulcia muelleri is to provide 10 essential amino acids to the pest insect Macrosteles quadrillineatus (Bennett et al).

What was sequenced?

10 phloem-feeding pest insects (Macrosteles quadrillineatus) including the obligate symbionts Nasuia deltocephalinicola & Sulcia muelleri.

Sequencing strategy: Whole genome sequencing

  1. Libraries & Sequencing: 2x 250 bp paired-end sequencing using the Illumina MiSeq platform
  2. Data output: 12,000 contigs (> 500 bp) including reads from the pest insect and Sulcia muelleri; MIRA and Velvet assembly revealed two large scaffolds for Nasuia (~102 kb & ~12 kb)
  3. Bioinformatics: Many tools have been used, including Velvet for inital read assembly; SOAP2 to map the symbion-derived reads to the Velvet contigs and MIRA for re-assembly of isolated symbiont reads

The biggest challenge with this genome mixture was definitely the bioinformatic analysis. During several cycles of mapping and assembly the reads that belong to one organism needs to be filtered out of the remaining reads. But this labour-intensive approach revealed the smallest bacterial genome yet sequenced (112 kb).

Read the complete publication here.

Whose Genome Has Been Sequenced? – Recent posts:

Stephanie Engel

About Stephanie Engel

Stephie's motto: NGS rules. She is thrilled by molecular diagnostics.

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