MultiVelo
中文導讀
MultiVelo(Nature Biotech)是 latent-time-based 的 multi-omics velocity 方法,接 RNA + chromatin(ATAC)。被 JianhuaXing 當反面教材點名:它的 velocity 跟 expression 不自洽 (velocity 說增加、expression 卻在減少),被當作「盲目用 ML、不顧理論」的例子(見 xing-hu-regvelo-debate);TopoVelo 也報告 MultiVelo 在 RNA vs ATAC modality 給出 inconsistent 結果。對照 GraphVelo 的 manifold-consistent 做法。
What it is
A multi-omics RNA-velocity method (Li, Virgilio, Collins & Welch, Nat Biotechnol 2022; multivelo-2022) that adds a third ODE for chromatin accessibility c(t) and gates transcription on it (α·c), jointly modeling epigenome→transcriptome timing from 10x Multiome / SHARE-seq. EM infers switch times, rates, a discrete state (primed / coupled-on / coupled-off / decoupled), and a gene-shared latent time. Welch lab — same lineage as VeloVAE / TopoVelo.
Physical-time scorecard
| Axis | MultiVelo |
|---|---|
| Latent time | ordinal (gene-shared, [0,1]); time lags as fractions, not hours |
| Rate scale | inherited; switch times on [0,1], no anchor |
| External anchor | none (snapshot multi-omic) |
| Constant rates | α chromatin-gated (relaxed); β, γ, chromatin rates constant |
| Verdict | epigenome-coupled α (mechanistic gain), temporally ordinal |
Why it appears here (negatively)
- JianhuaXing cites it as a cautionary case: its inferred velocity and expression are mutually inconsistent (velocity up while expression declines) — see xing-hu-regvelo-debate and velocity-skepticism.
- TopoVelo independently reports MultiVelo’s RNA- and ATAC-modality results were inconsistent on coarse-grained transition matrices.
- Contrast: GraphVelo’s tangent-space transfer (manifold-consistent-velocity) is offered as the self-consistent multi-omics alternative.
NOTE: fair-critique nuance (from multivelo-2022): the velocity↔expression “inconsistency” partly reflects intended decoupling modeling (chromatin and RNA legitimately move oppositely during priming/repression). The defensible critique is about downstream coarse-grained transitions being inconsistent (TopoVelo), not the ODE model itself.
Related
multivelo-2022 · GraphVelo · TopoVelo · VeloVAE · scVelo · grn-informed-velocity · JianhuaXing · latent-time · manifold-consistent-velocity · velocity-skepticism · RNA velocity