I have done 20 or 30 such operations in an afternoon, Spemann's induction experiment works like a charm In a few minutes, and next day a Siamese twin salamander will form! Call the National Inquirer With salamander gastrulas, you just cut out the dorsal lip of the blastopore with a sharp needle then slit open the blastocoel of another embryo, push this dorsal lip in through the hole, watch the hole heal Slow life-cycles (and also very large genomes) are big disadvantagesīut it's hard to do surgery on flies! Or even mice, or fish, or birds! Nuclear transplantation 'cloning' was first done using Rana frogs.Īnd the first adult animals produced this way were XenopusĪ breeding colony of Xenopus is kept at UVA, and another here.īreeding Axolotl colonies are at Indiana University, and U. Newts have more than 10 times as much DNA per cell as us. Still another advantage of newts is that they have VERY big cells.Ĭell size is linearly correlated with DNA amount, even "junk DNA"!!ĩ5% of biologists don't realize either fact, in my experience. It has never really been discovered why they regenerate so many organs that other vertebrates can't! Much is known but not the answer! Holtfreter earned his PhD doing research in Spemann's lab / early 1920s.Īnother advantage of newts is that they can regenerate their legs, regenerate the retinas of their eyes, the lenses of their eyes, etc. Holtfreter used salamander & frog cells to study cell sorting. Hans Spemann discovered embryonic induction of the neural tube by notochord mesoderm, using tissues from 2 newt species. The kinds used most have been Xenopus (an African frog), and Amblystoma (includes the Spotted Salamanders of the eastern US)Īnd also includes Axolotls (a semi-extinct Mexican Amblystoma) and also several kinds of Newts (a sub-group of salamanders) The core of what we know, or think we know, about mechanisms of development is extrapolated from surgical research on amphibian eggs. Thousands of research papers have been published on such experiments Frankenstein!BR>Īlways remember to build only very small monsters! It takes a few weeks to learn the art, but then you are Dr. Just keep the embryos is a very dilute salt (saline) solution,Īnd you can tear loose organs and just squeeze them next to another area where you have removed the skin, and they quickly seal into position. (Early salamander embryos repair wounds in minutes or hours.)įor example, you can graft limbs or heads, or areas of skin, etc. Lecture notes for Monday, Amphibian Embryo early development Frogs and salamanders are both amphibians, and have similar embryosįrom the late 1800s until after the mid-1900s, most of the best embryological research was done using salamander & frog eggsĮven tissue culture was invented using cells from frog embryos, and frog lymphĪdvantages of amphibian embryos for embryological research::ġ) Large size of embryos (several millimeters in diameter)Ģ) Tolerate surgery very well (although large cells are very fragile) Embryology Biology 441 Spring 2009 Albert Harris
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