Lineage tracing on transcriptional landscapes links state to fate during differentiation

May combine two claims.

Progenitors with different fate potentials did not split into discrete cell states but formed a structured continuum, matching recent scSeq studies.

“Consistent with recent scSeq studies (19), progenitors with different fate potentials did not partition into discrete cell states, but instead formed a structured continuum.”

• cites [19] sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

The high-dimensional character of scSeq permits multiple ways to build cell-state trajectories from one dataset.

“In addition, the high-dimensional nature of scSeq allows more than one approach to constructing cell state trajectories from the same data (4).”

• cites [4] sourceSupported

May combine two claims.

Single-cell RNA sequencing records mature cell types and every differentiation stage, yielding a state map in expression space.

“scSeq captures mature cell types alongside all stages of cell differentiation, revealing a ‘state map’ in gene expression space.”

• cites [3] sourcePartly supported

  In “Single-Cell Experimental Technologies to Interrogate Cell States From Tissues” (page unavailable), the paper says scRNA-seq measures gene expression and describes cell states as positions in a molecular-marker data space. It also says transitional states can be sampled to infer a continuum, but they are often rare and require dense sampling; it does not support the claim that sequencing captures every differentiation stage. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [4] sourcePartly supported

  The paper’s discussion of genome-scale single-cell measurements says scRNA-seq can generate an atlas of tissue cell states, and its hematopoiesis analysis describes a continuum of expression states at various stages of maturity. It does not say scRNA-seq captures every differentiation stage or necessarily includes mature cell types; the mapped endpoints in that analysis are identified as progenitors. No page numbers are available in our copy. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [5] sourceNot checked — no full text of the source
• cites [6] sourcePartly supported

  Figure 3 (Abstract; page unavailable) shows a gene-expression embedding containing major transient and mature cell subpopulations, supporting the idea of a state map. The paper does not establish that single-cell RNA sequencing captures *all* stages of differentiation; its abstract also describes each measurement as a static snapshot. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [7] sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Lineage tracing is the standard method for determining the relationship between progenitor cells and their descendants.

“The gold standard for inferring the relationship between progenitors and their offspring is lineage tracing, where a subset of progenitors is labeled, typically using genetic approaches that mark cells expressing defined marker genes, and their fate is profiled at a later time point (1).”

• cites [1] sourcePartly supported

  The Abstract describes fate maps as important tools for defining relationships between embryonic and later tissue structure, and Section 2 explains how genetic labeling tracks descendants over time. The paper supports the use of lineage tracing for this purpose, but does not establish the citing sentence’s stronger claim that it is the gold standard. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

May combine two claims.

Recent scSeq state maps, barcode-based clonal studies, and single-cell culture work indicate that traditional intermediate cell types are internally heterogeneous in state and fate potential, with HSPCs on a continuum rather than a stepwise hierarchy.

“But recent state maps from scSeq (9), as well as clonal studies using barcodes (10) and single cell culture (11), suggest that the traditional intermediate cell types are internally heterogeneous in state and fate potential, with HSPCs lying along a continuum of states rather than a stepwise hierarchy.”

• cites [9] sourceSupported
• cites [10] sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites [11] sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Earlier studies inferred lineage hierarchies from scSeq by assuming that cell types with similar expression trajectories share clonal origin.

“For cells undergoing multi-lineage fate choice, scSeq has been used to estimate lineage hierarchy based on the assumption that cell types with transcriptionally similar differentiation pathways are clonally related (3–5, 7).”

• cites [3] sourcePartly supported

  The ‘Downstream Analysis of Reconstructed Trajectories’ section (page unavailable) says that single-cell trajectories can indicate branching cell-fate decisions and hierarchical relationships. But ‘Notes on Using and Evaluating Trajectory Reconstruction Algorithms’ (page unavailable) distinguishes inferred cell-state transitions from parent–child lineage, which requires experimental validation; it does not establish that transcriptionally similar pathways imply clonal origin. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [4] sourcePartly supported

  The introduction says earlier single-cell methods fitted curves or trees to cell-state distributions to reconstruct differentiation trajectories, including branching ones. It does not say those studies assumed transcriptionally similar pathways imply clonal relatedness; that specific assumption is unsupported by our copy. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [5] sourceNot checked — no full text of the source
• cites [7] sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

This reasoning reflects the Data Processing Inequality.

“This reasoning reflects a formal result known as the Data Processing Inequality (20) (Supp Methods 10.1).”

• cites [20] sourceSupported

May combine two claims.

On the in vitro landscape, clones displayed uni-lineage and multi-lineage differentiation and self-renewal of early progenitors.

“On this landscape clones exhibited a range of behaviors including uni-lineage and multi-lineage differentiation, and self-renewal of early progenitors (Fig 1g).”

May combine two claims.

In the in vitro experiment, 38% of cells belonged to clones of two or more cells, comprising 5,864 clones.

“In these two experiments, 38% and 63% of cells respectively belonged to a clone of two or more cells (5864 and 7751 clones), with 1,816 and 817 clones in total spanning early and late timepoints (Fig 1d,i).”

May combine two claims.

Day 2 sister cells had correlated gene expression (median R=0.846), and 70% fell in the same or nearest neighbor cluster.

“We found that pairs of sisters profiled on day 2 localized in the SPRING graph, had correlated gene expression (median R=0.846) and that a majority (70%) fell in the same or nearest neighbor cluster (Fig 2a,b; Supp Fig 4a–d; Supp Methods section 5).”

May combine two claims.

In the transplantation experiment, 63% of cells belonged to clones of two or more cells, comprising 7,751 clones.

“In these two experiments, 38% and 63% of cells respectively belonged to a clone of two or more cells (5864 and 7751 clones), with 1,816 and 817 clones in total spanning early and late timepoints (Fig 1d,i).”

May combine two claims.

Where progenitors for different fates overlapped, bi-potent or oligopotent clones were observed, marking locations of fate commitment boundaries.

“Where the progenitors for different fates overlapped, we observed bi-potent or oligopotent clones, indicating the location of fate commitment boundaries (Fig 2d).”

May combine two claims.

The in vitro and transplantation experiments contained 1,816 and 817 clones, respectively, that spanned early and late time points.

“In these two experiments, 38% and 63% of cells respectively belonged to a clone of two or more cells (5864 and 7751 clones), with 1,816 and 817 clones in total spanning early and late timepoints (Fig 1d,i).”

May combine two claims.

A minority of sister cells diverged more, with 10% outside a four-cluster radius, compared with 80% for random cell pairs.

“A minority of cells, however, were more diverged, with 10% falling outside a four-cluster radius (compared to 80% for random cell pairs).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Megakaryocytes were not detected after transplantation, possibly because they did not survive bone marrow harvest, flow sorting, and single-cell encapsulation.

“We did not detect megakaryocytes, possibly because they did not survive bone marrow harvest, flow-sorting and single-cell encapsulation intact.”

May combine two claims.

Monocytes in the data spanned a continuum from neutrophil-like to DC-like, with some expressing Elane and other neutrophil markers and others expressing MHC-II genes including Cd74 and H2-Aa.

“In the data, monocytes appeared to form a spectrum from neutrophil-like to DC-like, expressing alternatively neutrophil elastase (Elane) and other neutrophil markers, or MHC class II components (Cd74 and H2-Aa) (Fig 4a).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The method can also be used for paired perturbation studies comparing sister cells exposed to different conditions.

“We demonstrated that this strategy can be simply extended to paired perturbation experiments that compare sister cells treated in different states.”

May combine two claims.

Across all conditions, the highest overall predictive accuracy from transcriptional state was 60% in vitro and 51% in vivo.

“Across all conditions, the highest overall predictive accuracy from transcriptional state was 60% in vitro and 51% in vivo.”

May combine two claims.

Post-transplantation, monocytes linked to DCs had higher DC marker expression, while those linked to neutrophils had higher neutrophil marker expression.

“As in vitro, the DC-related monocytes were enriched for DC marker genes, whereas neutrophil-related monocytes were enriched for neutrophil markers (Fig 4g,h).”

May combine two claims.

The best algorithms reached 76% accuracy in vitro and 70% in vivo when predicting late, versus 60% and 52% for early prediction.

“with the most accurate algorithms achieving late prediction accuracy of 76% in vitro and 70% in vivo, compared to 60% and 52% respectively for early prediction.”

May combine two claims.

The CD34+ multipotent progenitor fraction of day 2 cells contained broad domains: a restricted central Procr domain, a Gata2 wing, and an opposing Flt3 wing.

“The multipotent progenitor (CD34+) fraction of day 2 cells (Fig 2e) contained several broad domains, including a restricted central domain of stem cell marker (Procr) expression, a wing expressing Gata2 – an erythroid and stem cell marker – and an opposing wing expressing Flt3 indicative of lymphoid priming.”

May combine two claims.

Ikzf2 was enriched in eosinophil and mast cell progenitors but not in basophil or megakaryocyte progenitors.

“For example, Ikaros family zinc finger 2 (Ikzf2) – a myeloid leukemia gene not previously associated with fate choice – was enriched in eosinophil and mast cell progenitors, but not basophil or megakaryocyte.”

May combine two claims.

Transcription factors were only slightly more informative than random size-matched gene sets (10% more in vitro; 3% more in vivo), while differentially expressed genes were substantially more informative (38% more in vitro; 20% more in vivo).

“Transcription factors were only marginally more informative than random size-matched gene sets (10% more informative in vitro; 3% more informative in vivo), whereas differentially expressed genes were substantially more informative (38% more informative in vitro; 20% more informative in vivo).”

May combine two claims.

In classical monocytes and human peripheral blood monocytes, principal component analysis showed a spectrum of neutrophil-like to DC-like gene expression, also evident in marker gene expression.

“Second, we analyzed classical monocytes (Supp Fig 10g) and human peripheral blood monocytes (Supp Fig 10h) by scSeq. Principal component analysis shows that in both cases a spectrum exists of neutrophil-like to DC-like gene expression (see Table 8 for differentially expressed genes), which is also evident in the expression of marker genes (Fig 4i).”

May combine two claims.

Megakaryocyte, basophil, mast cell, and eosinophil potential were all confined to the Gata2+ region but came from separate subsets within it.

“Megakaryocyte, basophil, mast cell and eosinophil potential were all restricted to the Gata2+ region, yet derived from separate subsets within this region.”

May combine two claims.

In transplanted ST-HSCs and LT-HSCs, cells spanned a continuous landscape with primed-expression domains, including central Procr and opposing Gata2 and Flt3 wings, correlated with output into nine post-transplant fates.

“As before the cells spanned a continuous landscape with domains of primed gene expression, including a central domain of stem cell (Procr) and opposing wings of Gata2 and Flt3 expression (Fig 2h), that correlated with output into the nine respective post-transplant fates (Fig 2i).”

May combine two claims.

Among early Cd34+ progenitors, lineage data showed a monocyte-versus-neutrophil split that the algorithms mostly missed, though FateID did slightly better.

“but in the early progenitor (Cd34+) region, clonal tracking revealed a bifurcation of monocyte and neutrophil potential that was generally not detected by the prediction algorithms, although FateID performed slightly better (Fig 5c,d; R < 0.26 for all methods).”

Classified as probably not a substantial claim.

The prevailing hematopoiesis model is a branching hierarchy with defined fate-restricted intermediates.

“Cell culture and transplantation studies over several decades have led to the prevailing model of hematopoiesis as a branching hierarchy with defined fate-restricted intermediates (8).”

• cites [8] sourceNot checked — no full text of the source

May combine two claims.

These tests supported using clonal trajectories as approximations of single-cell trajectories, with some expected loss in fate-boundary resolution from the ~10% diverged sister pairs.

“These tests justified approximating single-cell trajectories by clonal trajectories, though with some loss in resolution of fate boundaries expected due to ~10% diverged sister pairs.”

May combine two claims.

scSeq data does not directly reveal when progenitors commit to fates or how many routes can reach the same terminal states.

“scSeq data does not directly report the stages at which progenitor cells become committed to one or more fates or how many distinct paths might lead cells to the same end states.”

May combine two claims.

LARRY is a lineage-tracing method compatible with scSeq that connects cell states to clonal outcomes at once from several starting conditions, without targeting individual progenitor states.

“LARRY defines a scSeq-compatible lineage tracing approach that links cell states to clonal fates simultaneously from multiple initial conditions, without needing to target each specific progenitor state.”

Probably not a substantial claim: may not pass S3 (load-bearing).

This analysis agrees with earlier observations.

“This analysis agrees with earlier observations (21).”

• cites [21] sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Earlier work reported that MDPs and GMPs produce monocytes with DC-like and neutrophil-like features, respectively.

“These results are consistent with a recent finding that immunophenotypically-defined monocyte-dendritic progenitors (MDPs) and granulocyte-monocyte progenitors (GMPs) give rise to monocytes with DC-like and neutrophil-like characteristics, respectively (21).”

• cites [21] sourceNot checked — no full text of the source

May combine two claims.

Differentiation follows a continuous, organized fate hierarchy whose clonal structure departs from classical tree models of hematopoiesis.

“and that cells differentiate via a continuous, structured fate hierarchy that differs from classical tree-like depictions of hematopoiesis in its clonal structure.”

May combine two claims.

The predictive content of HSPC gene expression measurements is almost entirely contained in several hundred differentially expressed genes and only marginally enriched in transcription factors.

“These results suggest that the predictive content of our gene expression measurements in HSPCs is almost entirely contained within several hundred differentially expressed genes, and only marginally enriched in transcription factors.”

May combine two claims.

Bipotent domains formed extended fate boundaries, suggesting differentiation can progress without fate commitment for some time.

“Further, bipotent domains formed extended fate boundaries, indicating that differentiation progression can occur independently of fate commitment over some time.”

May combine two claims.

Functional lineage priming varies across a continuous hematopoietic progenitor landscape and covaries with heterogeneous expression of genes, including transcription factors and other functional categories.

“Overall, these observations support the view that functional lineage priming varies across a continuous hematopoietic progenitor landscape and covaries with the heterogenous expression of genes, including transcription factors and a wide array of other functional gene categories.”

May combine two claims.

The observed DC-like and neutrophil-like routes probably correspond to MDP and GMP monocyte pathways, placing these states within an expression continuum.

“Thus, the DC-like and neutrophil-like trajectories observed here likely represent MDP and GMP pathways of monocyte differentiation, and they clarify the location of these states in a gene expression continuum.”

Probably not a substantial claim: may not pass S3 (load-bearing).

LARRY cannot study processes faster than one cell cycle.

“As with CRISPR-based approaches, the method cannot study processes faster than one cell cycle.”

Probably not a substantial claim: may not pass S3 (load-bearing).

MPP velocity differences might arise because cells stay in the MPP state for varying lengths before starting neutrophil differentiation.

“which could be explained by cells remaining in the MPP state for a variable duration before initiating neutrophil differentiation.”

May combine two claims.

The dataset thus reveals two separate monocyte differentiation routes, each with its own clonal links and expression changes.

“Our data therefore contains two different pathways of monocyte differentiation with distinct clonal relationships and gene expression dynamics.”

May combine two claims.

Each post-transplant fate outcome correlated with unique enriched genes before transplantation (n=190 [173 unique] DEGs at FDR=0.05), indicating specific priming at an early differentiation stage.

“Despite the less mature state of these cells, each fate outcome correlated with unique enriched genes prior to transplantation (Fig 2j; n=190 [173 unique] differentially expressed genes at FDR=0.05; Table 3), indicating a surprising degree of specific priming at this early stage of differentiation.”

Probably not a substantial claim: may not pass S3 (load-bearing).

LARRY does not require delivering multiple components.

“and it does not require delivering multiple components.”

May combine two claims.

The findings offer a way to compare differentiation models and could act as a benchmark for their improvement.

“These results provide a framework for comparing computational models of differentiation, and may serve as a useful benchmark for improving them.”

• AssumptionRests on an assumption: A shortage of ground-truth data has made it difficult to compare and validate current methods for modeling cell-state dynamics.

May combine two claims.

The gain in late-prediction accuracy is due to frequent agreement between sister cell fates and applies across clones of all potencies.

“These improvements in accuracy for late prediction reflect the high rate of concordance between sisters cell fates, and hold for clones of all potencies (Fig 3d)”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

This assumption may not always hold because similar end states could arise from non-overlapping clones and distant end states could share lineage through asymmetric division.

“Yet this assumption may not always hold: similar end states could also arise from non-overlapping clones (26) and distant end states could share lineage through asymmetric division.”

• cites [26] sourceNot checked — no full text of the source

May combine two claims.

Different clonal origins among monocytes pointed to progenitors with distinct fate capacities and perhaps distinct expression.

“The distinct clonal origins of monocytes suggested that they arise from progenitors with different fate potentials, and possibly different gene expression.”

Classified as probably not a substantial claim.

If no hidden variables exist, the information shared between separated sister cells could only decrease over time.

“If there were no hidden variables, we reasoned that the information shared between separated sister cells could only decrease as time passes.”

Probably not a substantial claim: may not pass S1 (asserted).

If stable properties influence cell fate but are hidden from scSeq, the mutual information between sisters could increase over time as those properties manifest in fate.

“Conversely, if there are stable properties that influence cell fate but are hidden from scSeq, then the mutual information between sisters could increase over time as these properties manifest in cell fate.”

Classified as probably not a substantial claim.

The findings favor using pseudotime approaches to map differentiation progression.

“These results support the use of pseudotime methods for mapping differentiation progression.”