Definition of blastoderm in US English:



  • 1The layer of embryonic tissue that forms prior to the development of the embryonic axis.

    • ‘In the fruit fly, segments are genetically delimitated early and simultaneously, when the embryo still is a blastoderm and the process of segmentation does not involve somites.’
    • ‘Early development is essentially two-dimensional; patterning occurs mainly in the blastoderm, the superficial layer of the embryo that consists first of nuclei and later of cells.’
    • ‘We examined Fumble staining during the mitotic divisions of the cellular blastoderm.’
    • ‘Apparently, there is little similarity between the simultaneous subdivision of the blastoderm into parasegments seen in Drosophila and the posterior addition of segments from a sub-terminal growth zone seen in many crustaceans.’
    1. 1.1 The outer layer of cells that forms the wall of a blastula.
      • ‘At cellular blastoderm most of the EAR protein is associated with cells at the periphery, while some protein is still associated with yolk nuclei.’
      • ‘When the membranes surrounding the peripheral nuclei fuse to form the 6000 cells of the cellular blastoderm, they enclose 175-225 polyploid yolk nuclei within a large syncytial yolk cell.’
      • ‘As a result, the blastodisc on the yolk becomes a blastoderm.’
      • ‘When the egg is laid, the blastoderm contains several hundred cells.’
      • ‘Pole cells cease dividing after the formation of the cellular blastoderm.’