The transfer of genetic diversity between spatially separated growing populations is relevant to a wide range of biological applications, including clonal diversity in cancer metastasis, clonal hematopoiesis in stem cell biology, and species diversity in ecology. We study a multitype branching process of population growth that originates from a single individual but over time receives additional migrants. We derive a surprisingly simple expression for the fraction of genetic diversity transferred between populations as a function of the immigration rates that connect them. Additionally, we calculate statistics for the fixation index FST between populations. Using this model framework, we analyze single-cell sequencing data from ovarian, breast, and colorectal cancer samples collected from 15 patients. For these genetically diverse cell populations, we find an average seeding rate of 1-10 migrant cells per cellular generation time. Under typical metastasis growth conditions, this estimate suggests that 16-130 cells seeded each metastasis and left surviving lineages. Since primary tumors are often surgically removed, the genetic diversity of these metastases determines the probability for treatment efficacy.This material is based on work supported by NSF Grant DGE 1144152 (A.H.).
APS March Meeting Abstracts
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