Measuring the distribution of fitness effects in somatic evolution by combining clonal dynamics with dN/dS ratios.

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Authors

Williams, MJ
Zapata, L
Werner, B
Barnes, CP
Sottoriva, A
Graham, TA

Document Type

Journal Article

Date

2020-03-30

Date Accepted

2020-03-09

Abstract

The distribution of fitness effects (DFE) defines how new mutations spread through an evolving population. The ratio of non-synonymous to synonymous mutations (dN/dS) has become a popular method to detect selection in somatic cells. However the link, in somatic evolution, between dN/dS values and fitness coefficients is missing. Here we present a quantitative model of somatic evolutionary dynamics that determines the selective coefficients of individual driver mutations from dN/dS estimates. We then measure the DFE for somatic mutant clones in ostensibly normal oesophagus and skin. We reveal a broad distribution of fitness effects, with the largest fitness increases found for TP53 and NOTCH1 mutants (proliferative bias 1-5%). This study provides the theoretical link between dN/dS values and selective coefficients in somatic evolution, and measures the DFE of mutations in human tissues.

Citation

eLife, 2020, 9

Source Title

Publisher

ELIFE SCIENCES PUBLICATIONS LTD

ISSN

2050-084X

eISSN

2050-084X

Research Team

Notes