Transplantation of anterior-limb mesoderm from Amblystoma embryos in the slit-blastopore stage
✍ Scribed by Detwiler, S. R.
- Publisher
- John Wiley and Sons
- Year
- 1929
- Tongue
- English
- Weight
- 444 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0022-104X
No coin nor oath required. For personal study only.
✦ Synopsis
NINE FIGURES
Much evidence has accumulated in recent years to show that the anterior-limb mesoderm of Amblystoma embryos in the tail-bud stage of development is irreversibly polarized along its anteroposterior (craniocaudal) axis (Harrison, '17, '21; Detwiler, '18, '20; Nicholas, '24; Swett, '27). When this axis is reversed at this stage, "The resulting limb has the asymmetry proper to the opposite side of the body from that on which it is placed, i.e., it is disharmonic, whether originally taken from the same or the opposite side" (Harrison's rule 1).
The results have shown, furthermore, that the other two axes (dorsoventral and mediolateral) at this stage are either indifferent o r have their polarity so lightly fixed that it may readily be overcome by the influences of the surrounding region.
Recently, Harrison ( '25) reversed the mediolateral axis and showed that the asymmetry or laterality of the resultant limb depends upon the orientation of the anteroposterior axis. When this is not reversed, the limb is harmonic regardless of the change in the mediolateral axis.
Swett ( '27) has reversed the dorsoventral and the mediolateral axes at successively older stages of development and has ascertained the stages during which these two axes become irreversibly fixed. Using Harrison's normal stages 315