1. Embryo Polarity and Pattern Formation14
Embryo Polarity and Pattern Formation

2. Polarity of the frog zygote

3. Importance of the gray crescent in frog development

4. Cleavage of the zygote of the sea snail, Ilyanassa

5. Experimental separation of cells after the 3rd cleavage in a sea urchin embryo

6. Spemann’s experimental transplantation of the gray crescent

7. Spemann’s experimental transplantation of the gray crescent

8. Development of vertebrate optic vesicles and their induction of lenses

9. Mammalian eye development

10. Mammalian eye development

11. Mammalian eye development

12. Amphibian gonad differentiation:
undifferentiated
gonad
presumptive ovarian tissue
presumptive testicular tissue
mature ovary
mature
testis

13. Homo sapiens genitalia differentiation

14. Homophilic binding of cell-adhesion proteins

15. A model of cell migration

16. Somite formation just prior to nerulation (cross section)

17. Somite formation just prior to nerulation (longitudinal section)

18. Model of morphogen concentration gradients in Drosophila differentiation of segmentation

19. Drosophila larval imaginal discs for corresponding adult appendages

20. A homeobox mutation in Drosophila

21. A homeobox mutation in Drosophila

22. Pattern formation in development of chick (Gallus gallus) wing

23. Pattern formation in development of chick (Gallus gallus) wing

24. Control development of chick (Gallus gallus) wing

25. Experimental grafting of progress zone in development of chick (Gallus gallus) wing

26. Experiment with a transplanted polarizing region

27. Control development of chick (Gallus gallus) wing

28. Regeneration of salamander arm

29. Migration of nerve cells

30. Growth cone of developing axon in grasshopper

31. Cell death (apoptosis) during the formation of nematode ganglion
Precursor 12 2 4 6 8 10 12
migration
mitosis
Time (hours) x x x
a b c d e S1 S2