PT  - JOURNAL ARTICLE
AU  - Lei Yu
AU  - Christoffer Boström
AU  - Sören Franzenburg
AU  - Till Bayer
AU  - Tal Dagan
AU  - Thorsten B.H. Reusch
TI  - Somatic genetic drift and multi-level selection in modular species
AID  - 10.1101/833335
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 833335
4099  - http://biorxiv.org/content/early/2019/11/07/833335.short
4100  - http://biorxiv.org/content/early/2019/11/07/833335.full
AB  - Cells in multicellular organisms are genetically heterogeneous owing to somatic mutations. The accumulation of somatic genetic variation in species undergoing asexual (or clonal) reproduction (termed modular species) may lead to phenotypic heterogeneity among modules. However, abundance and dynamics of somatic genetic variation under clonal growth, a widespread life history in nature, remain poorly understood. Here we show that branching events in a seagrass clone or genet leads to population bottlenecks at the cellular level and hence the evolution of genetically differentiated modules. Studying inter-module somatic genetic variation, we uncovered thousands of SNPs that segregated among modules. The strength of purifying selection on mosaic genetic variation was greater at the intra-module comparing with the inter-module level. Our study provides evidence for the operation of selection at multiple levels, of cell population and modules. Somatic genetic drift leads to the emergence of genetically unique modules; hence, modules in long-lived clonal species constitute an appropriate elementary level of selection and individuality.