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A. Morula and B. cross section of a blastula displaying the blastocoel and blastoderm of early animal embryonic development. Blastulation is the stage in early animal embryonic development that produces the blastula. In mammalian development, the blastula develops into the blastocyst with a differentiated inner cell mass and an outer trophectoderm.
Fish embryos go through a process called mid-blastula transition which is observed around the tenth cell division in some fish species. Once zygotic gene transcription starts, slow cell division begins and cell movements are observable. [4] During this time three cell populations become distinguished. The first population is the yolk syncytial ...
Coregonus is a diverse genus of fish in the salmon family ().The Coregonus species are known as whitefishes.The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate.
There is much variation among the European whitefish forms, but in general they have a tapered body, a slightly protruding upper jaw and a fleshy dorsal fin that is typical of the salmon family. The snout is short and tapered, a fact that distinguishes this species from the two other North European Coregonus species, vendace ( Coregonus albula ...
While mitosis can occur in the absence of cytokinesis, cytokinesis requires the mitotic apparatus. The end of cleavage coincides with the beginning of zygotic transcription. This point in non-mammals is referred to as the midblastula transition and appears to be controlled by the nuclear-cytoplasmic ratio (about 1:6).
The broad whitefish is a herring-shaped fish with a more compressed body and convex head than other whitefishes. It is iridescent, with a dark olive-brown back, silvery grey sides, and a whitish bottom. [2] [3] Features that distinguish it from other species include a mild overbite and 18–25 short gill rakers.
During this stage, the embryo is referred to as a blastula. The series of changes to the blastula that characterize the midblastula transition include activation of zygotic gene transcription, slowing of the cell cycle, increased asynchrony in cell division, and an increase in cell motility.
The whitefish is part of the salmon family, and the distinctive traits of this subfamily (in comparison to the rest of the salmon family) include larger scales, smaller mouth, weak or no teeth, and other internal characteristics. [6] The round whitefish is a cylindrical fish (hence cylindraceum) and is considered a deep-bodied fish. It is ...