Evolution of a system sensitive to stochastic noise: P3.p cell fate in Caenorhabditis.

摘要: The C. elegans cell lineage is overall invariant. One rare instance of variability concerns P3.p, the most anterior vulva precursor cell, which may either fuse with epidermis without dividing, or remain competent to form vulval tissue and divide. Here we examine evolutionary properties this stochastic variation in P3.p fate. In Caenorhabditis genus, high competence ancestral reduction division frequency occurred sp. 14 a clade nine species. Within clade, further varies within among species, being intermediate low briggsae. fate sensitive random mutation accumulation, suggesting that trait evolve rapidly because its sensitivity mutational impact. depends on LIN-39/Hox5 expression find peak protein level displaced posteriorly briggsae compared elegans. However, specification dose EGL-20 CWN-1, two Wnts are secreted long-range gradient from posterior end larvae (accompanying article). A half-dose these sufficient affect N2 levels similar those Symmetrically, show an increase Wnt rescues We propose concentration interpretation be involved rapid evolution Caenorhabditis.