Gene action on proliferation and migration in the developing neural crest of black and white axolotls,Ambystoma mexicanum,Shaw
✍ Scribed by Borack, Leonard I.
- Publisher
- John Wiley and Sons
- Year
- 1972
- Tongue
- English
- Weight
- 802 KB
- Volume
- 179
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
The mitotic index number of cells of the neural crest and its derivatives in situ was determined i n serially-sectioned embryos of the black (DD or Dd) and white (dd) strains of the Mexican axolotl, Ambystoma mexicanum, S k u , to see whether the differences between the strains in the number and distribution of their initial complement of melanophores could be causally related to differences i n the pattern of development of their respective neural crests.
Prior to and during the initial appearance of melanophores, the mitotic index of the neural crest in situ i n the black axolotl is significantly greater than in the white. Concommitantly, there are more crest cells in the black than in the white prior to crest cell migration. However, during the periods of maximum crest cell migration and initial appearance of melanophores, there are significantly more crest cells in situ in the white than i n the black. These crest cells in situ i n the white are clumped together mid-dorsal to the neural tube, while in the black they show the dispersion typical of migrating crest cells.
Following the initial appearance of melanophores, there are no differences between the strains in the number of melanophores dorsal to the neural tube and somites, but there are significantly more crest-derived cells in this area in the black than in the white. The latter difference between the strains may be causally related to the significantly greater number of cells i n the early spinal ganglia of the black axolotl than in the white.