When pairs of human 23 and mouse 20 homologs are compared, the genes located on either side also tend to be homologs. This relationship is called synteny

TLS Online TPP Program

#Id: 1047

#Unit 5. Developmental Biology

The cells found within the most posterior region of the progress zone constitute the zone of polarizing activity.

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#Id: 1048

#Unit 5. Developmental Biology

Sonic hedgehog, is the major active factor in the ZPA. 

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#Id: 1049

#Unit 5. Developmental Biology

The apical ectodermal ridge is a thickening of the ectoderm at the apex of the developing limb bud.

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#Id: 1050

#Unit 5. Developmental Biology

Fgf8 is the major active factor in the AER.

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#Id: 1051

#Unit 5. Developmental Biology

Homeobox transcription factors, or Hox genes, play an essential role in specifying whether a particular mesenchymal cell will become stylopod, zeugopod, or autopod.

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#Id: 1052

#Unit 5. Developmental Biology

Hox9 and Hox10 paralogues specify the stylopod