1. the larger cells produced during the early stages of embryonic development when an egg undergoes unequal cell division
Usage: biology; embryology

Examples

• The macromeres contain most of the yolk and develop more slowly than the smaller cells.
• During cleavage, the embryo divides into macromeres and micromeres.
• Scientists observed that macromeres give rise to the endoderm in many species.
• The unequal distribution of nutrients between macromeres and micromeres affects cell fate.
• In sea urchin development, macromeres are clearly distinguishable from the smaller cells.
• Researchers studied how macromeres contribute to early embryonic patterning.