part_of part of part of results in formation of results in formation of anatomical entity rhombomere formation rhombomere 1 morphogenesis rhombomere 1 formation biological_process GO:0021652 The process that gives rise to rhombomere 1. This process pertains to the initial formation of a structure from unspecified parts. Rhombomeres are transverse segments of the developing rhombencephalon. Rhombomeres are lineage restricted, express different genes from one another, and adopt different developmental fates. Rhombomeres are numbered in anterior to posterior order. anatomical structure formation involved in morphogenesis rhombomere 1