* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Course Name: Advanced Topics in Developmental Biology Course
Human–animal hybrid wikipedia , lookup
Oncogenomics wikipedia , lookup
Human genome wikipedia , lookup
Behavioral epigenetics wikipedia , lookup
Human genetic variation wikipedia , lookup
Genetically modified food wikipedia , lookup
Essential gene wikipedia , lookup
Pathogenomics wikipedia , lookup
Epigenetics in stem-cell differentiation wikipedia , lookup
Transgenerational epigenetic inheritance wikipedia , lookup
Public health genomics wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Gene expression profiling wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Ridge (biology) wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Microevolution wikipedia , lookup
Genetic engineering wikipedia , lookup
Genomic imprinting wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genome evolution wikipedia , lookup
Designer baby wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Minimal genome wikipedia , lookup
Course Name: Advanced Topics in Developmental Biology Course number: 47020634 Lecturer: Dr. Claytus Davis ([email protected]) Hours: one two-hour session once a week for one semester Format: student-led discussion/argument based on research articles. Topics: are all chosen for their controversial nature and include, among others: Redundancy in embryonic development, Regeneration, Prokaryotic multicellularity, epigenetic inheritance. Marking: 50% will be a written work, 50% will be a subjective evaluation of participation in discussion Language: English with Hebrew as needed. Course is limited to 15 students maximum More detailed information is at URL: http://fohs.bgu.ac.il/develop/db2.html 1. Haploid/Prokaryotic development Although most organisms on the planet are bacteria, almost all complex multicellular organisms belong to the plants or animals. Although all of these plants and animals have haploid/diploid lifecycles, it almost always the diploid phase that forms a complex organism. Why? 2. Redundancy in developmental programs Seventy years ago, Hans Spemann suggested that some developmental events were so important that the organisms developed two independent, redundant mechanisms to ensure that the event proceeded normally (double assurance). More recently, it has been shown that a large number of genes thought to be involved in regulating mouse development show no phenotype when they are "knocked out". Are they part of double assurance pathways? The idea of double assurance makes the evolutionary biologists uneasy. Who is right? 3. Is the mouse an upside-down lobster? The location of the neural tube, the primary dorsal/ventral asymmetry of the basic body plan, is ventral in the arthropods and dorsal in the vertebrates. Over a hundred and fifty years ago it was suggested that both the vertebrates and the invertebrates had the same fundamental body plan - one of them was just living on its back. This idea was thoroughly ridiculed. New molecular data suggests a reassessment. 4. Human embryonic stem cells: the shape of science and ethics Embryonic stem cell are derived from the very early embryo and are totipotent – capable of becoming any cell type in the body. They can also be modified genetically in vitro. We can produce designer mice and we can almost certainly produce designer humans. Where do we stop? 5. Regeneration and Spallanzani’s mouse A bisected planaria is able to regenerate the entire organism. A cockroach can regenerate a missing leg. Some lizards can do the same. Humans can regenerate nothing more complicated than a finger tip. Why are we so bad at regeneration compared to many other animals? 6. L/R axis formation In all vertebrates the left side of the animal is different than the right side. Failure to place the organs on the proper side can be lethal. The left-right axis is the last embryonic axis defined during embryogenesis. Once the anterio-posterior and dorsoventral axes are set, there is only one possible left and right. But how does the embryo know which side is which? 7. When does development end? Embryonic development is the execution of a genetic program. From the point of view of the organism, birth or hatching just marks a change of environment. Genetically programmed changes in structure and function continue at least until sexual maturity. Does the program stop there? Is senescence genetically programmed? 8. A phylotypic stage? Haekel proposed that all vertebrate embryos pass through a phylotypic stage – an embryonic stage where all vertebrates look the same – at this stage a fish embryo looks just like a human embryo. Is there such a thing? 9. Losing your ancestral genes Embryonic development is the result of the execution of a genetic program. Some of the pieces of this program are genes that play central roles in regulating this process. They have been conserved for hundreds of millions of years. Now that we have started looking at whole genomes we find that some of these genes have been lost in some animals. How is this possible? How can an ancient, conserved, and important gene be lost without negative effect? 10. Epigenetic inheritance The information used during embryonic development to construct the body is considered to be encoded in the genome. But is this always true? To what extent can an epigenetic state be transmitted through the germ line into the next generation? Was Lamark perhaps a little bit right? 11. The heart never forgets It is the brain that thinks. But does it think alone? Is thinking a cooperative process - with other body parts participating? For instance, do your thoughts belong, in part, to your heart? 12. Where are all those disease genes? We were very successful identifying genes associated with simple single-locus, mendelian-inheritance genetic diseases. Some more complicated inheritances, like that of X-linked mental retardation took a little longer. The human haplotype and single nucleotide polymorphism maps were supposed to help us identify the collection of genes associated with more complex diseases, like type2 diabetes. The results have been disappointing. What’s going on? Why are we failing? 13. Why are sponges stupid? What started with the human genome has now advanced to the sponge. Surprise. They have many of the genes that regulate complex embryonic development, for instance the genes defining muscle and brain. Why does a thing that has been sitting on the bottom for 700 million years without moving or reacting have these genes? 14. What is life? - the title of Irwin (let’s make waves) Schrödinger’s 1944 book. So, 66 years later, and as we are discovering planets in the “Goldilocks Zone” of other stars, how would you like to define life?