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Headline: All arabica coffee is genetically similar But: > The study found evidence of significant chromosomal rearrangements, especially in a varietal of C.
by jl6 3y ago
Headline: All arabica coffee is genetically similar
But:
> The study found evidence of significant chromosomal rearrangements, especially in a varietal of C. arabica called Bourbon. There were deletions, in which fragments of chromosomes were missing — in some cases large chunks — and even instances in which entire chromosomes were absent.
Does this really count as genetically similar? I would have imagined that the presence and order of genes was an important aspect of genetic variation.
- photochemsyn 3y agoThe paper itself goes into some more detail on that - the genetic diversity is found in the organization of the units among the chromosomes, while the units themselves (e.g. caffeine biosynthesis genes etc. are identical). This results in variations in gene expression levels, which alone is apparently enough to produce distinct varietals. > "While none of the different chromosomal aberrations we have identified is introducing new sequence variants, they are all capable of altering gene dosage between homoeologs and also total gene dosage in the case of aneuploidies, deletions and duplications. These changes in gene copy number may result in expression differences and this in turn may result in significant phenotypic variation, as shown by aneuploid somaclonal variants that frequently originate from tissue culture and somatic embryogenesis. The genomic rearrangements may therefore represent an important source of genetic diversity that is continuously replenishing the very limited nucleotide diversity available within the species." https://www.nature.com/articles/s41467-023-44449-8 https://www.nature.com/articles/s41467-023-44449-8 I suppose the takeaway is that using functional gene sequences alone (a common approach in the pre-whole-genome sequenceing era) to determine genetic similarity misses a lot of important information.
- tobinfricke 3y agoYeah the subtitle kinda contradicts the title: "Flavour variations are mainly the result of changes at the chromosome level, sequencing effort finds."
- cortesoft 3y agoYeah, I mean technically people and coffee are genetically similar.
- anon84873628 3y agoNot to mention ignoring Hibrido de Timor and its now popular decent Catimor.