Inference of trajectory presence by tree dimension and subset specificity by subtree cover.

The complexity of biological processes such as cell differentiation is reflected in dynamic transitions between cellular states. Trajectory inference arranges the states into a progression using methodologies propelled by single-cell biology. However, current methods, all returning a best trajectory...

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Main Authors: Lovemore Tenha, Mingzhou Song
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-02-01
Series:PLoS Computational Biology
Online Access:https://doi.org/10.1371/journal.pcbi.1009829
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author Lovemore Tenha
Mingzhou Song
author_facet Lovemore Tenha
Mingzhou Song
author_sort Lovemore Tenha
collection DOAJ
description The complexity of biological processes such as cell differentiation is reflected in dynamic transitions between cellular states. Trajectory inference arranges the states into a progression using methodologies propelled by single-cell biology. However, current methods, all returning a best trajectory, do not adequately assess statistical significance of noisy patterns, leading to uncertainty in inferred trajectories. We introduce a tree dimension test for trajectory presence in multivariate data by a dimension measure of Euclidean minimum spanning tree, a test statistic, and a null distribution. Computable in linear time to tree size, the tree dimension measure summarizes the extent of branching more effectively than globally insensitive number of leaves or tree diameter indifferent to secondary branches. The test statistic quantifies trajectory presence and its null distribution is estimated under the null hypothesis of no trajectory in data. On simulated and real single-cell datasets, the test outperformed the intuitive number of leaves and tree diameter statistics. Next, we developed a measure for the tissue specificity of the dynamics of a subset, based on the minimum subtree cover of the subset in a minimum spanning tree. We found that tissue specificity of pathway gene expression dynamics is conserved in human and mouse development: several signal transduction pathways including calcium and Wnt signaling are most tissue specific, while genetic information processing pathways such as ribosome and mismatch repair are least so. Neither the tree dimension test nor the subset specificity measure has any user parameter to tune. Our work opens a window to prioritize cellular dynamics and pathways in development and other multivariate dynamical systems.
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spelling doaj.art-60c03bc1265144bea420736bbcc153b72022-12-22T02:37:16ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582022-02-01182e100982910.1371/journal.pcbi.1009829Inference of trajectory presence by tree dimension and subset specificity by subtree cover.Lovemore TenhaMingzhou SongThe complexity of biological processes such as cell differentiation is reflected in dynamic transitions between cellular states. Trajectory inference arranges the states into a progression using methodologies propelled by single-cell biology. However, current methods, all returning a best trajectory, do not adequately assess statistical significance of noisy patterns, leading to uncertainty in inferred trajectories. We introduce a tree dimension test for trajectory presence in multivariate data by a dimension measure of Euclidean minimum spanning tree, a test statistic, and a null distribution. Computable in linear time to tree size, the tree dimension measure summarizes the extent of branching more effectively than globally insensitive number of leaves or tree diameter indifferent to secondary branches. The test statistic quantifies trajectory presence and its null distribution is estimated under the null hypothesis of no trajectory in data. On simulated and real single-cell datasets, the test outperformed the intuitive number of leaves and tree diameter statistics. Next, we developed a measure for the tissue specificity of the dynamics of a subset, based on the minimum subtree cover of the subset in a minimum spanning tree. We found that tissue specificity of pathway gene expression dynamics is conserved in human and mouse development: several signal transduction pathways including calcium and Wnt signaling are most tissue specific, while genetic information processing pathways such as ribosome and mismatch repair are least so. Neither the tree dimension test nor the subset specificity measure has any user parameter to tune. Our work opens a window to prioritize cellular dynamics and pathways in development and other multivariate dynamical systems.https://doi.org/10.1371/journal.pcbi.1009829
spellingShingle Lovemore Tenha
Mingzhou Song
Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
PLoS Computational Biology
title Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
title_full Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
title_fullStr Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
title_full_unstemmed Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
title_short Inference of trajectory presence by tree dimension and subset specificity by subtree cover.
title_sort inference of trajectory presence by tree dimension and subset specificity by subtree cover
url https://doi.org/10.1371/journal.pcbi.1009829
work_keys_str_mv AT lovemoretenha inferenceoftrajectorypresencebytreedimensionandsubsetspecificitybysubtreecover
AT mingzhousong inferenceoftrajectorypresencebytreedimensionandsubsetspecificitybysubtreecover