Upgrading short read animal genome assemblies to chromosome level using comparative genomics and a universal probe set

Joana Damas, Rebecca O'Connor, Marta Farré, Vasilis Lenis, Henry Martell, Anjali Mandawala, Katie Fowler, Sunitha Joseph, Martin Swain, Darren Griffin, Denis Mikhailovich Larkin

Research output: Contribution to journalArticlepeer-review

68 Citations (SciVal)
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Abstract

Most recent initiatives to sequence and assemble new species' genomes de-novo fail to achieve the ultimate endpoint to produce contigs, each representing one whole chromosome. Even the best-assembled genomes (using contemporary technologies) consist of sub-chromosomal sized scaffolds. To circumvent this problem, we developed a novel approach that combines computational algorithms to merge scaffolds into chromosomal fragments, PCR-based scaffold verification and physical mapping to chromosomes. Multi-genome-alignment-guided probe selection led to the development of a set of universal avian BAC clones that permit rapid anchoring of multiple scaffolds to chromosomes on all avian genomes. As proof of principle, we assembled genomes of the pigeon (Columbia livia) and peregrine falcon (Falco peregrinus) to chromosome level comparable, in continuity, to avian reference genomes. Both species are of interest for breeding, cultural, food and/or environmental reasons. Pigeon has a typical avian karyotype (2n=80) while falcon (2n=50) is highly rearranged compared to the avian ancestor. Using chromosome breakpoint data, we established that avian interchromosomal breakpoints appear in the regions of low density of conserved non-coding elements (CNEs) and that the chromosomal fission sites are further limited to long CNE 'deserts.' This corresponds with fission being the rarest type of rearrangement in avian genome evolution. High-throughput multiple hybridization and rapid capture strategies using the current BAC set provide the basis for assembling numerous avian (and possibly other reptilian) species while the overall strategy for scaffold assembly and mapping provides the basis for an approach that (provided metaphases can be generated) could be applied to any animal genome.
Original languageEnglish
Pages (from-to)875-884
Number of pages10
JournalGenome Research
Volume27
Issue number5
Early online date30 Nov 2016
DOIs
Publication statusPublished - 01 May 2017

Keywords

  • Animals
  • Avian Proteins/genetics
  • Chromosome Breakpoints
  • Chromosomes/genetics
  • Columbidae/genetics
  • Conserved Sequence
  • Contig Mapping/methods
  • Falconiformes/genetics
  • Genome
  • Genomics/methods
  • Reference Standards

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