BRAINCAKEBody Plans
Hox genes in animals are the homeobox genes that control body plans. Animals are segmented. There are maternal effect genes which control the polarity (direction) of the body, segmentation genes which control the polarity of each segment and homeotic selector genes which determine the identity of each segment. All the tissues and organs of the body develop from 2 - 3 primary tissue layers (primary germ layers). In mammals, there are 3: the endoderm, ectoderm and mesoderm. Segments in the embryo (somites) controlled by hox genes develop in the order in which the hox genes are expressed. The hox genes are expressed in the order in which they appear on the chromosome.
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Key terms in this lesson
- Homeobox gene
- A gene containing a highly conserved 180-base sequence, the homeobox, that codes for a DNA-binding domain controlling the expression of other genes involved in development and body plan.
More in Genetics and Variation
- Post-transcriptional control
- Translational Control
- Post-translational Control
- Homeobox Genes
- Apoptosis
- Regulatory Genes
- Variation
- Body Mass
All 36 lessons in Genetics and Variation · All OCR A-level Biology topics