How does coverage of all contigs varies?

Question

[BioGeek]

How does coverage of all contigs varies? Why contaminants contigs have various coverage in an assembly?

[WouterDeCoster]

This question could use more information and context, please elaborate.

Answer 1

[h.mon]

Read about coverage here, here, here and here. There are plenty of other sources, just google for "sequencing coverage" and variants.

Contaminants usually have lower and more variable coverage because they are non-obvious, small introductions of extraneous material into the source material, which can occur at many steps from biological sample collection to library preparation to sequencing.