J Syst Evol

• Research Article •     Next Articles

From genomes to graphs: why macroevolution still matters in the pangenome era

Bin-Bin Liu1,2*   

  1. 1 Key Laboratory of Systematic and Evolutionary Botany/State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;
    2 China National Botanical Garden, Beijing 100093, China
    *Author for correspondence. E-mail:liubinbin@ibcas.ac.cn
  • Received:2026-04-12 Accepted:2026-07-08 Online:2026-07-08
  • Supported by:
    Financial support for this work was provided by the National Natural Science Foundation of China (grant numbers 32570240, 32270216, and 32000163 to BBL), the Youth Innovation Promotion Association CAS (grant number 2023086 to BBL), and the Biological Resources Programme, Chinese Academy of Sciences (CAS-TAX-24-013 to BBL).

Abstract: As genomics moves from multilocus datasets to pangenomes and graph genome representations, the main challenge is no longer only to detect variation, but also to explain how genomic features are distributed across lineages. Pangenomes and graph genomes reveal structural variants, alternative haplotypes, lineage-specific sequences and complex patterns of lineage sharing. These signals, however, do not by themselves show whether a pattern reflects common ancestry, retained ancestral polymorphism, introgression, recurrent origin or analytical artifact. This problem is especially acute in clades shaped by hybridization, introgression and polyploidy, where a single bifurcating tree may be useful for some questions but misleading for others. Here, we argue that the pangenome era increases the need for explicit macroevolutionary coordinates. We propose a conservative evidence ladder that treats conflict first as an observation, evaluates incomplete lineage sorting and analytical artifacts before stronger process claims are made, and then considers introgression, backbone-level reticulation, and, when necessary, polyploid-aware interpretation. For many downstream questions, the useful output may be a compressed reticulate backbone rather than a fully elaborated network. Such a backbone should be auditable and should retain only those departures from treeness that change comparative, functional, breeding-oriented or taxonomic interpretation. Examples from crop pangenomes, Rosaceae, and other conflict-rich systems illustrate how macroevolutionary reasoning can improve the interpretation of micro-scale genomic signals in the pangenome era.

Key words: evidence ladder, graph genome, macro-to-micro inference, pangenome, reticulate backbone