Group items tagged

Embryo Images Normal and Abnormal Mammalian Development is a tutorial that uses scanning electron micrographs (SEMs) as the primary resource to teach mammalian embryology. The 3-D like quality of the micrographs coupled with selected line drawings and minimal text allow relatively easy understanding of the complex morphological changes that occur in utero. Because early human embryos are not readily available and because embryogenesis is very similar across mammalian species, the majority of micrographs that are utilized in this tutorial are of mouse embryos. The remainder are human.

A handful of scientists around the United States are trying to do something that some people find disturbing: make embryos that are part human, part animal. The researchers hope these embryos, known as chimeras, could eventually help save the lives of people with a wide range of diseases.

Following on the achievements of Chinese researchers, scientists in the United States have used CRISPR to manipulate the genomes of viable human embryos, MIT Technology Review reported yesterday (July 26). The work, not yet published, reportedly corrected defective genes from sperm donors in dozens of embryos, which were allowed to grow for several days.

The Visible Embryo is a visual guide through fetal development from fertilization through pregnancy to birth. As the most profound physiologic changes occur in the "first trimester" of pregnancy, these Carnegie stages are given prominence on the birth spiral.

A British researcher has received permission to use a powerful new genome editing technique on human embryos, even though researchers throughout the world are observing a voluntary moratorium on making changes to DNA that could be passed down to subsequent generations.

Phys.org) -Scientists at the University of Virginia School of Medicine have overcome one of the greatest challenges in biology and taken a major step toward being able to grow whole organs and tissues from stem cells. By manipulating the appropriate signaling, the U.Va. researchers have turned embryonic stem cells into a fish embryo, essentially controlling embryonic development.

Aneuploidy-the incorrect number of chromosomes in a cell-is extremely common in early embryos and is the primary reason for pregnancy loss. A report published today (April 9) in Science reveals that one cause of this aneuploidy-aberrant cell divisions in the embryo-is linked to a genetic mutation carried by the mother. Astonishingly, this mutation turns out to be very common and appears to have been under positive selection during human evolution.

More than 400 scientists, bioethicists, and historians from 20 countries on 6 continents have gathered this week in Washington, DC, for the Human Gene Editing Summit. The attendees are a veritable who's who of genome editing: Jennifer Doudna of the University of California, Berkeley, Emmanuelle Charpentier of Max Planck Institute for Infection Biology, and Feng Zhang of the Broad Institute of MIT and Harvard-the three discoverers of the CRISPR-Cas9 system's utility in gene editing-plus dozens of other big names in genome science. Cal Tech's David Baltimore along with the heads of the four national societies hosting the meeting (US National Academy of Sciences, US National Academy of Medicine, Chinese Academy of Sciences, and the U.K.'s Royal Society) provided opening remarks on Tuesday (December 1). And as I sat stage right in the NAS auditorium, I noticed the unmistakable rear profile of Harvard Medical School's George Church three rows in front of me. Church was scheduled to speak at a session later that afternoon about the application of CRISPR and other new precision gene editing techniques to the human germline-a hot-button topic since April, when a Chinese group published it had successfully modified the genomes of human embryos, and the National Institutes of Health (NIH) said it would not fund such research. Then in September, the U.S./U.K.-based Hinxton Group, an international consortium of scientists, policy experts, and bioethicists, said it supported the use of genetic editing in human embryos for limited applications in research and medicine.  

imaging of embyro collection

nique mutations used to trace history back to its origins in the embryo Date: June 29, 2014

Chinese scientists say they've genetically modified human embryos for the very first time. The team attempted to modify the gene responsible for beta-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. Gene editing is a recently developed type of genetic engineering in which DNA is inserted, replaced, or removed. Here, experts weigh-in with ethical questions and considerations.

Odyssey of life animations: human, pig, chicken, and fish embryos

For the first time, biologists have succeeded in growing human stem cells in pig embryos, shifting from science fiction to the realm of the possible the idea of developing human organs in animals for later transplant.

This 5 lesson unit, which was designed by teachers in conjunction with scientists, ethicists, and curriculum developers, explores the scientific and ethical issues involved in stem cell research. The unit begins with an exploration of planaria as a model organism for stem cell research. Next, students identify stages in the development of human embryos and compare the types and potency of stem cells. Students learn about a variety of techniques used for obtaining stem cells and the scientific and ethical implications of those techniques. While exploring the ethics of stem cell research, students will develop an awareness of the many shades of gray that exist among positions of stakeholders in the debate. Students will be provided an opportunity to become familiar with policies and regulations for stem cell research that are currently in place in the United States, the issues regarding private and public funding, and the implications for treatment of disease and advancement of scientific knowledge. The unit culminates with students developing a position on embryonic stem cell research through the use of a Decision-Making Framework. Two culminating assessments are offered: In the individual assessment, students write a letter to the President or the President's Bioethics Committee describing their position and recommendations; In the group assessment, students develop a proposal for NIH funding to research treatment for a chosen disease using either embryonic or 'adult' stem cells.

Stem Cell Overview Article with embedded Video 7:53 Discusses gene expression/differentiation 2 minute segments -Pluripotent stem cells in early embryo CDX2 OCT3/4, Inner cell mass start- 1:50 - Characteristics of Stem Cells: differentiation, abilities of stem cells,  1:55- 3:17 - Stem Cells in the Adult Body: red blood cell hematopoetic stem cells, differentiation, small intestine crypts,  3:20-5:35 - Embryonic Stem Cells in Culture: ES pluripotent cells ES cells, treat to neural lineages, culture conditions, study differentiate into lineages 5:40- 7:53

1:30 animation As a human embryo develops, its cells become progressively restricted in the types of specialized cells that they can produce. Inner cell mass (ICM) cells of the blastocyst can make any type of body cell. Gastrula-stage cells can give rise to the cells of a given germ layer. Later, cells become even more restricted. For example, the pancreatic bud of the endoderm layer can only make the cells of the pancreas.

This page shows some key events of human development during the embryonic period of the first eight weeks (weeks 1 - 8) following fertilization. This period is also considered the organogenic period, when most organs within the embryo have begun to form. There are links to more detailed descriptions which can be viewed in a week by week format, by the Carnegie stages or integrated into a Timeline of human development. Online resources available include: individual images of all Carnegie stages, scanning electron micrographs of the earlier stages, cross-sections showing internal structures at mid- and late-embryonic, 3D reconstructions of internal structures, animations of processes, ultrasound scans and information about abnormalites of development.

The most recent human retroviral infections leading to germ line integration took place with a subgroup of human endogenous retroviruses called HERVK(HML-2). The human genome contains ~90 copies of these viral genomes, which might have infected human ancestors as recently as 200,000 years ago. HERVs do not produce infectious virus: not only is the viral genome silenced - no mRNAs are produced - but they are littered with lethal mutations that have accumulated over time. A recent study revealed that HERVK mRNAs are produced during normal human embryogenesis. Viral RNAs were detected beginning at the 8-cell stage, through epiblast cells in preimplantation embryos, until formation of embryonic stem cells (illustrated). At this point the production of HERVK mRNA ceases. Viral capsid protein was detected in blastocysts, and electron microscopy revealed the presence of virus-like particles similar to those found in reconstructed HERVK particles. These results indicate that retroviral proteins and particles are present during human development, up until implantation.

The early stages of embryonic development shape our cells and tissues for life. It is during this time that our newly formed cells are transformed into heart, skin, nerve or other cell types. Scientists are finding that this process is largely controlled not by the genome, but by the epigenome, chemical markers on DNA that tell cells when to turn genes on and off. Now, studying zebrafish embryos, researchers at Washington University School of Medicine in St. Louis have shown that the epigenome plays a significant part in guiding development in the first 24 hours after fertilization.

The uproar over the new ease and precision with which scientists can manipulate the DNA of living things has centered largely on the complicated prospect of editing human embryos. But with the federal government's approval last week of a fast-growing salmon as the first genetically altered animal Americans can eat, a menagerie of gene-edited animals is already being raised on farms and in laboratories around the world - some designed for food, some to fight disease, some, perhaps, as pets.