@article {Rozhok181065, author = {Andrii I. Rozhok and James DeGregori}, title = {On somatic constraints in the evolution of multicellularity}, elocation-id = {181065}, year = {2017}, doi = {10.1101/181065}, publisher = {Cold Spring Harbor Laboratory}, abstract = {The evolution of multi-cellular animals has produced a conspicuous trend toward increased body size in many animal taxa. This trend has introduced at least two novel problems: the elevated risk of somatic disorders, such as cancer, and drastically declining evolvability due to reduced population size, lowered reproduction rate and extended generation time. Low population size has been argued to explain the higher mutation rates observed in animals compared to unicellular organisms. Here, we present theoretical evidence from stochastic modeling that the evolution of extended lifespans dramatically alters selection acting on germline mutation rates. We demonstrate that this effect significantly impacts evolvability while limiting somatic risks in populations of large animals. We propose a theoretical model for how evolvability and germline mutation rates can be under positive selection. We argue that this mechanism may have been critical in enabling the evolution of large multi-cellular animals.}, URL = {https://www.biorxiv.org/content/early/2017/08/25/181065}, eprint = {https://www.biorxiv.org/content/early/2017/08/25/181065.full.pdf}, journal = {bioRxiv} }