In homeotic transformation, a normal body part is replaced by a body part which is regularly found in other regions.
| Example | Overview |
|---|---|
| Antennapedia | Antennapedia mutants of Drosophia have antennae replaced by legs. |
| Ultrabithorax | Ultrabithorax (Ubx) mutants of Drosophila have halteres (T3) replaced by wings (T2), imparting four total wings. |
| Invertebrate | Vertebrate |
| Nematode | Xenopus |
| Drosophila | Chicken |
| Sea Urchin | Zebrafish |
| Mouse |
Different model organisms are used to study development, chosen for their: length of embryonic development: length of life cycle; size of organism; ease of lab growth; size of genome; number of chromosomes; and experimental techniques available for that organism. Embryos that develop internally are difficult to see and manipulate, as they embed into the mother’s uterus. Large embryos are easier to directly manipulate (ie, tissue transplantation). Large adult organisms are space- and money-consuming versus smaller organisms, which can be easier to analyze and in large numbers.
| Organism | Pros | Cons | Tools | Notes |
| Drosophila | Small organisms. Large litters. Fast development External development |
Genetic screens. Other excellent tools. |
||
|---|---|---|---|---|
| Mouse | Mammal. | Internal development. Small litter. Relative large. |
Many excellent tools. | |
| Xenopus | Very large embryos. External development. |
Tetraploid. | Few genetic tools. | Genetic tools are being developed for diploid frog species. |
| Zebrafish | Vertebrate. Large embryos. External development. Many progeny. |
Excellent genetic tools. | ||
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