add 2022 JGI Petabyte Scale Sequence Search workshop slideshow into docs

[ctb]

https://hackmd.io/_h-BqlNWS4uqb9LkiOeALg

Fractional sketches

or, some details of how sourmash and FracMinHash work!

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Consider overlaps between k-mers extracted from three genomes - two that share sequence, and one that does not.

From these we can calculate k-mer based similarity measures (Jaccard similarity and containment).

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FracMinHash sketching compresses k-mer collections while retaining set relationships

This is implemented in the software sourmash.

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These Jaccard (k-mer) measures can be translated to ANI

Credits: Dr. Tessa Pierce-Ward et al; more info.

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References:

FracMinHash and sourmash - Lightweight compositional analysis of metagenomes with FracMinHash and minimum metagenome covers, Irber et al. 2022

ANI calculations - Debiasing FracMinHash and deriving confidence intervals for mutation rates across a wide range of evolutionary distances, Hera et al., Hera et al., 2022