BIO 112 Lecture Notes - Lecture 11: Hox Gene, Fetus, Morphogenesis
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How are the genes in a hox cluster expressed during early development (see figure 2). Segments would be out of order if it moves into genome. In vertebrates, the hox genes also pattern the developing limbs along the proximal distal(p-d) axis. Hox 9 group genes pattern the proximal elements, hox 10 group genes pattern slightly more distal elements, Hox 11 group genes more distal etc. the see figure below: Less is known about the role of hox genes in other organs. Different hox genes have various effects on how the lungs form into lobes, make correct shape and size, etc. During embryogenesis a fine balance exists between cell proliferation and differentiation, which is essential for normal development of the fetus. In contrast in cancer the balance between the two processes goes awry as reviewed by grier et al (page 29, 2nd column).
