Assembly of the Flax Genome into Chromosomes


You FM, Cloutier S (2019) Assembly of the Flax Genome into Chromosomes. In: Genetics and Genomics of Linum, Plant Genetics and Genomics: Crops and Models 23, Cullis CA (ed), Springer Nature, Switzerland, Chap 5,

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Flax, whose latin name Linum usitatissimum means most useful, is a rare crop with two main products. The fibres extracted from its stems are weaved into long lasting linen fabrics or transformed into various non-woven products. Flaxseed, also called linseed, is rich in omega-3 fatty acid, making praised in the food and nutraceutical industries as well as an industrial oil for the production of linoleum flooring, paint and inks for examples. Here, we produced the complete DNA sequence of the flax genome through the integration of sequencing data from multiple technologies with genetic, physical and optical maps. The final results of this multi-dimensional integration is the production of a comprehensive genome sequence properly ordered and assigned to the 15 chromosomes of flax. This effort represents a major improvement over the initial draft genome assembly that promises to be useful for genome evolution studies, comparative genomic analyses, genetic research and molecular breeding.


Flax (Linum usitatissimum L., 2n = 2x = 30) has two main products: its seed, rich in nutritional omega-3 fatty acids, and its strong and long-lasting high tensile strength fibre extracted from the straw. Identification and utilization of the genes affecting the yield and quality of these bioproducts are expected to contribute to the improvement of flax and other oil- and fibre-producing species. Genomic resources, especially a complete flax genome reference sequence, promise to facilitate this process. The flax genome was sequenced, and the first draft reference sequence was released in 2012 (Wang et al. 2012). Also, a large number of flax genomic resources have been produced, such as bacterial artificial chromosome (BAC) libraries, a BAC-based physical map, BAC-end sequences (BES) (Ragupathy et al. 2011), simple sequence repeat (SSR) marker-based genetic map (Cloutier et al. 2012), high-density single nucleotide polymorphism (SNP) marker-based genetic map and a BioNano genome optical map (You et al. 2018). Integration of these genomic resources assisted in the validation and ordering of the draft reference sequence into chromosomes, resulting in a higher-quality flax reference sequence, useful for genome evolution studies, comparative genomic analyses, genetic research and molecular breeding (You et al. 2018).

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