Multiclonality

Multiclonality is the condition in which a population or sample contains multiple genetically distinct clonal lineages. It contrasts with monoclonality, where a single clonal lineage predominates. The concept is used across biology to describe genetic heterogeneity within a single tumor, tissue, or ecological community, and it often implies ongoing clonal evolution.

In cancer biology, multiclonality refers to intratumor heterogeneity, where subclones derive from a common ancestral cell but accumulate distinct mutations. Subclones can differ in growth rate, metastatic ability, and drug sensitivity. The structure can be described as a branched evolutionary tree, with clonal sweeps and private mutations shaping the tumor under selective pressures such as therapy and microenvironmental factors.

In microbiology and ecology, multiclonality describes communities containing multiple genetic lineages or strains. In plants, stands may be multiclonal when composed of several genetically distinct individuals or clones. In infectious diseases, diverse pathogen populations can coexist within a host or environment, affecting virulence and treatment outcomes.

Detecting multiclonality relies on sequencing approaches that resolve genetic variation across cells or genomes. Bulk sequencing can infer subclonal structure from variant allele frequencies and copy-number profiles, while single-cell sequencing can map individual subclones directly. Understanding multiclonality has implications for prognosis and treatment in cancer, and for ecology and agriculture in non-cancer contexts. Challenges include sampling bias, data interpretation, and distinguishing true subclones from technical noise.