The movies listed on this page are wonderful; because they make development directly visible. I have downloaded these movies from other web sites, with permission of the authors, in order to give students at UT Austin faster access to them. I will add more movies to this site as they come to my attention and as I get permission. If you come across a good movie that you think should be added to this page, send an e-mail to the address at the bottom of this page.
To view these movies, you need a program called "QuickTime". If you don't have it, you can download it tfrom the internet.
Frog Oogenesis. Frog oocyte shown in lateral view. The movie reveals the massive increase in volume of the oocyte and the pigmentation that distinguishes the animal from the vegetal hemisphere. Downloaded with permission from the Amphibian Embryology Tutorial by Dr. Jeff Hardin at the University of Wisconsin.
Movies on Fertilization
Calcium Wave at Fertilization. The entry of the fertilizing sperm triggers the release of calcium ions from the egg's endoplasmic reticulum. The release of calcium ions sweeps across the egg in a wave starting at the point of sperm entry. To view this phenomenon, go to to Lionel Jaffe's Calcium Tsunami web site and click on any of the photographic images.
Implantation of Human Embryo. This animated movie shows the implantation into the uterine lining of a human embryo, as seen in section. Implantation begins at the end of the first week, when the embryo attaches to the uterine wall. The conceptus is completely beneath the uterine surface by the end of the second week. The amniotic cavity (red) lies above the embryonic disc, and the yolk sac cavity (yellow) lies below. The outermost layer of the embryo, the syncytiotrophoblast, produces the enzymes to dissolve the maternal tissue, and the amount of syncytiotroblast increases dramatically during the second week. J
Zebrafish Early Cleavage. This zebrafish embryo is stained with Bodipy 505/515, which stains yolk platelets brightly and cytoplasm more weakly. Nuclei remain unstained and thus appear as dark circles. The blastomeres undergoing meroblastic cleavage in the lower portion of the image are connected by cytoplasmic bridges to the uncleaved yolky part of the egg. During every prophase there is a major onset of motility of the yolk platelets. The platelets are pulled into tubular forms, sometimes fragmenting. During telophase and interphase, the platelets re-coalesce into spherical bodies. Larger yolk platelets tend to be localized in the peripheral cytoplasm of cleaving blastomeres. Also notice the periodic fragmentation of the yolk mass within the uncleaved part of the egg. Downloaded from the FishScope website by Dr. Mark S. Cooper at the University of Washington, Seattle.
Movies on Axis Formation and Mesoderm Induction
Cortical Rotation. This is a lateral view of a frog zygote seen from the left side. Dorsal is to the right, ventral to the left, anterior near the top. On the dorsal side, cortical cytoplasm rotates upward in relation to the underlying yolky inner cytoplasm that remains in place. Rotation is driven by a layer of microtubules at the vegetal (bottom) side. The sperm entry point would be at the upper left. Most of the pigment granules are in the cortical cytoplasm of the animal pole, so the pigment boundary rotates upward on the dorsal side, revealing the more sparsely pigmented inner cytoplasm and thus delineating the gray crescent. J
Live Frog Gastrulation: Posterior/Dorsal View. This video sequence provides a posterior and dorsal view of the embryo's surface during gastrulation. The "dirty frown", visible at the beginning of the movie, marks the dorsal lip of the blastopore. It spreads laterally and then ventrally to form a complete circle. The cells surrounding the blastopore move to the inside through the process of involution. Meanwhile, those cells that remain outside undergo a spreading movement known as epiboly, which ends with an almost complete constriction of the blastopore. This constriction is asymmetrical, proceeding faster on the dorsal side, which is elongating towards the viewer at the end of the movie. The constricted blastopore will develop into the anus at the posterior end of the embryo; the mouth is formed secondarily at the anterior end, which is facing away from the viewer. The movement that makes the embryo elongate anteroposteriorly while shrinking laterally is known as convergent extension. Downloaded with permission from the Amphibian Embryology Tutorial by Dr. Jeff Hardin at the University of Wisconsin.
Animated Frog Gastrulation: Posterior/Dorsal View. This movie was made by Dr. Steven Black (Reed College at Portland, OR) on the basis of the detailed drawings published in the classic book by P.D.Nieuwkoop and J. Faber (1967) Normal Table of Xenopus laevis (Daudin). 2nd ed. Amsterdam: North Holland Publishing Company. This animated sequence begins with the same gastrulation movements also shown in other movies on this web site, and it continues with the formation of the neural plate on the dorsal side of the embryo. The view is from dorsoposterior. The narrow posterior region of the neural plate will form the spinal cord while the wide anterior region will give rise to the brain. Downloaded with permission from the Amphibian Embryology Tutorial by Dr. Jeff Hardin at the University of Wisconsin. Other animated movies show in color the movements of the superficial layer and deep involuting marginal zone. J
Live Frog Gastrulation in Median Optical Section. This movie shows an optical section of a living embryo, made possible by advanced light microscopy. The section is along the median plane, which separates the right and left halves of the embryo. The animal pole is at the top, the dorsal side to the right. The epiboly of the outer cell layer, and the closure of the blastopore near the bottom, are easily visible. The involution of cells around the blastopore lips can also be seen, especially on the dorsal side. Note the faint dark line on the dorsal side that separates the involuted layer (future notochord and roof of the embryonic gut) from the outer layer (future neural plate). The movie also shows how the original cavity of the embryo, the blastocoel, collapses while the cavity of the embryonic gut expands. Downloaded with permission from the Amphibian Embryology Tutorial by Dr. Jeff Hardin at the University of Wisconsin.
Keller Sandwich Cutout This animated movie shows diagrammatically how a Keller open-face sandwich (explant) is cut out from the dorsal lip of the blastopore of a frog embryo. Red: dorsal mesoderm that normally involutes and elongates; Blue: ectoderm that does not involute, but does elongate; Green: epidermis that does not involute nor elongate. J
Live Dorsal Lip Explant A living dorsal lip explant (Keller openface sandwich), obtained as shown in the Keller Sandwich Cutout movie, is viewed from the basal side. The dorsal mesoderm, which would have involuted, is at the right, the noninvoluting ectoderm at the left (darker). The broad initial explant is elongated by convergence extension which occurs only in the mesoderm in these openface sandwiches. J
Dorsal Lip Explant Animated This is an animated version of the Live Dorsal Lip Explant movie. Two dorsal lip explants (removed as shown in sandwich-cutout mov) are combined with basal surfaces together and with their ectoderm (blue) and mesoderm (red) in register. While only mesoderm elongates in openface sandwiches, both ectoderm and mesoderm elongate in these doubled sandwiches. Mesoderm elongation occurs somewhat earlier than does ectodermal elongation.
Drosophila Gastrulation and germ band formation is shown in dorsolateral view. Anterior is to the left, dorsal side up. The movie begins with late cleavage, when the pole cells (to the right) are already formed. Blastoderm cells on the ventral side (hidden from view) form the germ anlage, which extends posteriorly until the posterior tipo is positioned right behind the head capsule. Subsequently, this movement is reversed as the germ anlage develops into a segmented germ band. The flanks of the germ band then begin to grow together dorsally in a process known as dorsal closure. For more movies on Drosophila gastrulation and germ band formation, go to Thom Kaufman's Fly Morph-O-Genesis web site and click on any of the photographic icons.
Thin Filopodia in Sea Urchin Gastrulation. In sea urchin gastrulae, mesenchyme cells extend thin filopodia (0.2 - 0.4 Ám in diameter). These thin filopodia don't seem to be used for locomotion. Rather, they appear to assess their environment like the thin filopodia seen at the tips of axon growth cones. To view thin filopodia, go to Jeff Miller's Dynamics of Thin Filopodia web site and click on any of the photographic icons.
Frog Gastrulation and Neurulation. This video of a living Xenopus (frog) embryo was made in the lab of Ray Keller at Berkeley. It shows both gastrulation and neurulation. The view is dorso-posterior. At the beginning, the dorsal lip of the blastopore is the dark crescent near the top. The future lateral lips and ventral lip of the blastopore are lightly outlined in pigment patches. That lateral and ventral lips quickly form, enclosing a large yolk plug that fills the now-completed blastopore. The blastopore closes as the dorsal mesoderm and the neural plate elongate the axis by convergent extension. The open neural plate on the dorsal side has formed by the time the blastopore closes. The closure of the neural plate into a tube is accompanied by a great elongation of the hindbrain and spinal cord. Downloaded with permission from the Amphibian Embryology Tutorial by Dr. Jeff Hardin at the University of Wisconsin.
Dishevelled in Xenopus Neurulation. Four embryos are followed though gastrulation and neurulation (stage 11.5-22.0). Gastrula stages are seen from the blastopore. As neurulation begins, the embryos are rotated to present a dorsal view. The top left embryo has been injected with mRNA encoding a defective version (Xdd1) of the Xenopus ortholog of the Drosophila dishevelled protein. The embryo fails to close its neural tube. The lower left embryo is an uninjected control. The two right embryos were also injected with Xdd1 but have managed to close their neural tubes anyway. An additional movie shows a dorsal view of three neurulating Xenopus embryos (stage 16-21). The left embryo is expressing Xdd1 and fails to close its tube. The middle embryo is also expressing Xdd1 but successfully closes its neural tube. The right embryo is an uninjected control. From the Data Supplement to Wallingford J.B. and Harland R.M. (2002) Neural tube closure requires Dishevelled-dependent convergent extension of the midline. Development 129: 5815-5825
Human Organogenesis. This animated sequence shows the development of a human embryo from the end of the 4th week to the end of the 7th week after fertilization. Downloaded from The Multi-Dimensional Human Embryo, is a collaboration funded by the National Institute of Child Health and Human Development (NICHD) to produce and make available over the internet a three-dimensional image reference of the Human Embryo based on magnetic resonance imaging.
Human Embryological Development is a web site constructed by U.S. National Museum of Health and Medicine. It contains an extensive collection of animations of human development from gametogenesis to organogenesis.
You can find links to websites with more movies by going to Related Web Sites.
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Last modified: 09 October 2003