How mutation accumulation depends on the structure of the cell lineage tree

Area of Science:

• * Evolutionary biology
• * Cancer research
• * Cellular dynamics

Background:

• * Multicellular organisms develop from single cells through cell divisions, forming a cell lineage tree.
• * Replication errors during cell division introduce mutations, driving somatic evolution and potentially leading to cancer.
• * The structure of the cell lineage tree significantly impacts the accumulation of mutations and cancer progression.

Purpose of the Study:

• * To develop a method for calculating the probability of accumulating mutations within cell lineage trees.
• * To analyze the relationship between cell lineage tree shape and cancer development.
• * To understand the role of natural selection in shaping cell lineages and controlling somatic evolution.

Main Methods:

• * Modeled mutation accumulation as a graph theoretical problem.
• * Developed an exact numerical method to compute the probability of acquiring a specific number of mutations.
• * Derived an analytical approximation for low mutation rates.

Main Results:

• * The probability of mutation accumulation is dependent on the distribution of lineage lengths within the cell tree.
• * Longest lineages play a dominant role in determining mutation accumulation probability.
• * An analytical formula approximates mutation probability for low mutation rates.

Conclusions:

• * Cell lineage tree shape is a critical factor in somatic evolution and cancer risk.
• * Understanding lineage length distribution is essential for predicting mutation accumulation.
• * Natural selection actively shapes cell lineage trees to limit somatic evolution and cancer development.