arXiv:2605.21859q-bio.PEcs.LG2026-05

用混合流模型在树空间中高效生成进化树,提升贝叶斯推断速度与精度。

PhylaFlow: Hybrid Flow Matching in Billera-Holmes-Vogtmann Tree Space for Phylogenetic Inference

论文配图:PhylaFlow: Hybrid Flow Matching in Billera-Holmes-Vogtmann Tree Space for Phylogenetic Inference
图 1 · 摘自论文原文
  • 结合连续分支长度与离散拓扑变化,在BHV树空间中设计混合流匹配模型
  • 在8个数据集上显著降低初始树的KL差异,提升拓扑恢复效率
  • 适合需要快速精准推断进化关系的研究者,尤其适用于复杂案例

系统发育树是混合对象:分支长度连续变化,拓扑结构通过边收缩与展开离散改变。Billera-Holmes-Vogtmann(BHV)树空间为此类结构提供了标准几何,将每个解析拓扑表示为欧氏正交锥,拓扑变化表现为跨共享低维边界运动。我们提出PhylaFlow,一种在BHV树空间中学习后验盆地传输的混合流匹配模型。该模型在从随机起始树到短时后验采样路径的测地线上训练,同时耦合正交锥内的连续分支长度运动与学习到的边界事件和离散拓扑转换。通过操作性评估:若流能抵达后验相关区域,则从其终态树出发或受其引导的有限预算贝叶斯精炼应更高效地恢复支持的拓扑。在DS1-DS8共8个系统发育后验基准测试中,PhylaFlow显著降低初始树的树KL值。经有限预算MrBayes精炼后,直接使用PhylaFlow在多数数据集上改善早期与中期拓扑恢复轨迹;分枝引导的PhylaFlow-MCMC在困难案例中表现最佳。最优变体在7/8数据集上优于短预热方法,5/8数据集上优于PhyloGFN,且在联合序列条件实验中,序列嵌入可引导后验分裂恢复,但精确拓扑恢复仍处于初步阶段。结果表明,混合流匹配可在BHV树空间中学习可行动态传输,并为贝叶斯系统发育推断提供几何感知提议机制。

原文摘要 · Abstract (English)

Phylogenetic trees are hybrid objects: branch lengths vary continuously, while topologies change discretely through edge contractions and expansions. Billera-Holmes-Vogtmann (BHV) tree space provides a canonical geometry for this structure, representing each resolved topology as a Euclidean orthant and topological changes as motion across shared lower-dimensional boundaries. We introduce PhylaFlow, a hybrid flow-matching model that learns posterior-basin transport in BHV tree space. PhylaFlow is trained on BHV geodesic paths from random starting trees to short-run posterior samples, coupling continuous branch-length motion within orthants with learned boundary events and discrete topology transitions. We evaluate the learned geometry operationally: if the flow reaches posterior-relevant regions, finite-budget Bayesian refinement initialized from, or guided by, its terminal trees should recover posterior-supported topologies more efficiently. Across DS1-DS8 phylogenetic posterior benchmarks, PhylaFlow substantially reduces initial Tree-KL relative to classical initializers. After finite-budget MrBayes refinement, direct PhylaFlow improves early and intermediate topology-recovery trajectories on most datasets, while split-guided PhylaFlow-MCMC obtains the strongest hard-case results. The best PhylaFlow variant outperforms short-warmup on seven of eight datasets and PhyloGFN on five of eight under the same refinement budget. In a joint sequence-conditioned experiment, sequence embeddings steer posterior split recovery, although exact posterior topology recovery remains preliminary. These results show that hybrid flow matching can learn actionable transport in BHV tree space and provide a geometry-aware proposal mechanism for Bayesian phylogenetic inference.

系统发育流模型贝叶斯推断树空间

Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。