negative regulation of histone H3-K27 trimethylation
Known as: down regulation of histone H3-K27 trimethylation, down-regulation of histone H3-K27 trimethylation, downregulation of histone H3-K27 trimethylation
Any process that stops, prevents or reduces the frequency, rate or extent of histone H3-K27 trimethylation. [GOC:TermGenie, PMID:19270745]