Animal Development

A list of different animal embryos that have been used in embryology studies that can be found within the UNSW Embryology program.

The links are to more detailed pages with overviews of embryological development and the key experimental findings. There are also links to external resources and labs that use these models. Use the title below to open pages with more about information about that animals embryo development and additional pages that relate to that species.

UNSW Embryology Links

Bat

• Bat
• Not a typical embryo used in developmental studies, but first alphabetically and an alternative mammalian model. A recent paper has detailed the short-tailed fruit bat (Carollia perspicillata) embryonic stages of development.

Bovine

• Bovine
• Not a typical embryological model, but extensively studied due to commercial value and more recently for breeding using IVF techniques. Development takes about 280 days.

Chicken

• Chicken | Chicken Development Stages | Chicken Early Development
• The chicken embryo develops and hatches in 20-21 days and historically these were one of the first embryos to be studied. Cutting a window in the egg shell allows direct observation of the embryo. The Hamburger & Hamilton chicken development staging allowed researchers to develop this model as a key embryological tool.
• Key research involved the transplanting of quail cells into chick embryos, to later identify their contribution to different embryonic structures, particularly for somite, neural tube and neural crest development.

Echidna

• Echidna
• Not a typical embryo used in developmental studies, much work is still required to determine this unique monotreme embryonic stages of development.

Fly

• Fly
• The fruitfly (drosophila) was and is the traditional geneticist's tool. It has been transformed to an magnificent embryologist's tool, with developmental mechanisms being uncovered in this system combined with homolgy gene searches in other species. The fly genome was one of the first to be been completely sequenced.
• In early development nurse cells sacrifice their cytoplasmic contents to allow egg growth and early pattern formation is through the localization of maternal messenger RNAs (mRNAs).

Frog

• Frog | Frog Life Cycle | Frog Gastrulation | Frog Localized mRNA
• The frog was used by many of the early embryology investigators and currently there are many different molecular mechanisms concerning development of the frog.
• The eggs develop independently, in relative synchrony and are relatively see-through making staging and observation fairly easy.
• The frog was a key model for the study of the process of gastrulation.

Guinea Pig

• Guinea Pig
• The guinea pig has been used as a model animal in many animal model studies; developmental, dietary, tetragenic, including the effects of maternal temperature on development.

Mouse

• Mouse | Mouse Stages | Mouse Timeline (day by day) | Mouse Detailed Timeline (day by day) | Mouse Estrous Cycle | Mouse Heart
• The mouse has always been a good embryological model, easy to generate (litters 8-20) and quick (21d).
• Mouse embryology really expanded when molecular biologists used mice for gene knockouts.

Platypus

• Platypus
• Not a typical embryo used in developmental studies and we still no very little about the embryonic stages of this unique monotreme development.
• The platypus has an amazing sex chromosome organization,

Rabbit

• Rabbit
• The rabbit along with human, are the few species which show birth defects with thalidomide (teratogenic effects) which were not detected with prior testing on other species.

Rat

• Rat | Rat Estrous Cycle
• The rat is available as inbred, outbred and mutant strains. They have been generally beaten as a model by their mice brethren, as the molecular tools that became available (stem cells, knockout genes, etc). Rat embryos do have the advantage of being much larger than mouse embryos and easy to breed. Rat development is also generally 1 day behind from mouse.

Worm

• Worm
• Early embryological studies of the worm Caenorhabditis elegans (C.Elegans, so called because of its "elegant" curving movement) characterized the fate of each and every cell in the worm through all stages of development. This worm has recently had its entire genome sequenced.

Zebrafish

• Zebrafish
• Zebrafish are seen as the latest and greatest "model' for embryological development studies. They can be easily genetically altered and develop as practically "see through" embryos, all internal development can be clearly observed from the outside in the living embryo.

Medaka Fish

• Medaka Fish
• The Japanese rice fish (Oryzias latipes) is a member of the killifish family and used in several developmental studies.

Missing Species

• These species have been used in a variety of developmental studies, but I have not yet developed an online resource.

• Axolotl - (Ambystoma mexicanum) A salamander where the larvae do not undergo metamorphosis and adults remain gilled and aquatic. The ability to regenrate limbs has been used to study developmental pattern formation and nerve regeneration. Also used to investigate neural crest migration.

• Sea Urchin - A species used to study very early development from fertilization onward.

Other Pages

• Embryo Staging Systems - stages are based on the external and/or internal morphological development of the vertebrate embryo, and are not directly dependent on either age or size.

• Carnegie Comparison - the human embryonic period proper is divided into 23 Carnegie stages. Criteria beyond morphological features include age in days, number of somites present, and embryonic length. This staging can be applied to all vertebrates, and most vertebrate embryos develop during the embryonic period in much the same way, we can directly compare the timing of development for different species.

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

---

Cite this page: Hill, M.A. (2024, May 2) Embryology Animal Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Animal_Development

What Links Here?

© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G