Epigenetic Control of Animal Development - Building the Most Complex Structure on Earth - page 147

Chordates

Craniates

Vertebrates

Tr ue brain, cranial neural crest,
placodes

Neural tube, notochord

Dorsal neural tissue

Figure 3.22 Features associated with the evolution of the chordate/vertebrate dorsal neural
tube are shown in this phylogenetic tree. NCCs and placodes are vertebrate features that
follow the evolution of a neural tube and notochord.
Source : From Hall (2009) , modified from Holland and Graham (1995) .

Ectoderm

NC

NT

Figure 3.23 Cranial NCC migration starts around Hamburger and Hamilton (HH) Stage 11
in chick. The lead cranial NCCs emerge from the dorsal neural tube (beige) within a short
distance from the dorsal neural tube, they acquire directionality (yellow NCCs).

Source : From Kulesa et al. (2010) .