Identifying developmental genes dev't biology


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Identifying developmental genes dev't biology

  1. 1. Developmental Biology Report prepared by: John Michael P. Angelo Registered Professional Teacher SNCECM Math Coordinator MAT-Biology Student Identifying Developmental Genes
  2. 2. Genes that are developing Animals Plant  Mouse (Mus musculus)  Zebrafish (Danio reno)  Fruit fly (Drosophila melanogaster)  C. elegans (Caenorhabditis elegans)  African clawed frog (Xenopus laevis)  Chick (Gallus gallus domesticus)  Thale cress (Arabidopsis thaliana)  Maize (Zea mays L. spp. mays)  Snapdragon (Antirrhinum)  Petunia (Petunia hybrida)  Physcomitrella patens (physcomitrella patens)
  3. 3. We can identify developmental genes by the following comparisons 1. Multicellularity 2. Cell movement 3. Rigidity of the body shape 4. Multicellular stages 5. Meiosis 6. Germline 7. Morphogenesis 8. Plasticity
  4. 4. Multicellularity  The multicellularity of the animals and plants mechanisms is developed independently. Explanation:  That mechanism in the comparison of the genes between the animals and plants makes up the body plan of plants and animals.  While the homeobox and MADS box genes existed in last common ancestor, the MADS box gene plays the role of regulation of plant development while the homeobox genes are important in animals.
  5. 5. MADS-Box Genes  This is a conserved sequence motif found in genes which comprise the MADS-box gene family.  This box encodes the domain of DNA-binding MADS. This domain allows to bind DNA sequences of high similarity to the CC[A/T]6GG motif known as CArG-box.  The domain of DNA-binding MADS are called transcription factors.
  6. 6.  According to various researchers, the lengths of this box were in the range between 168 to 180 base pairs and that is the encoded MADS domain which has the length of 56 to 60 amino acids.  The MADS domain is evolved, according to some evidences, that there is a sequence stretch of a type II topoisomerase (or cutting of both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils) in a common ancestor of all extant eukaryotes.
  7. 7. The name of the MADS-Box Genes  M – MCM1 from the budding yeast  A – Agamous from the thale cress  D – Deficiens from the snapdragon  S – SRF from the human  Agamous – is a gene and transcription factor for the thale cress.  SRF – also known as Serum response factor
  8. 8. Serum response factor  It is a transcription factor that can be found in humans.  It is considered very important especially in the development of the embryo as it has been linked to the formation of mesoderm.
  9. 9. Function 1. In animals, they are involved in muscle development, cell proliferation and differentiation. This ranges from the pheromone response to arginine metabolism. 2. In plants, they are involved in controlling all major aspects of development especially in the development of gametophytes, embryo, seed, root, flower and fruits in both male and female.
  10. 10. 3. They have homeotic functions like the homeobox (or HOX) genes of animals. While Agamous and Deficiens for the plants participates in the determination of floral organ identity according to the ABC model of flower development. 4. The flowering time determination is also a factor in the MADS-box gene. It has been shown to have an important role in the integration of molecular flowering time pathways.
  11. 11.  The genes of the 4th function are essential for the timing of the flower bloom correctly and fertilization helps to ensure it at the time of the maximum reproductive potential.
  12. 12. Homeobox or Hox Genes  They are a group of related genes that controls the body plan of the embryo along the anterior- posterior (or head-tail) axis.  Properties: 1. Protein product is a transcription factor. 2. DNA sequence called homeobox is present 3. This are present in animals because of the same order of the expression along the head- tail axis of the developing animal.
  13. 13. Cell Movement Animals Plants  Motile animal cells  Positionally fixed plant cells
  14. 14. Animal cells are motile.  The tissues may be folded and moved against each other easily.  On the gastrulation of metazoan, triple layered system is built (first layer – entoderm, second layer – mesoderm, third layer – ectoderm)  They may even move to other sites autonomously.
  15. 15. Plant cells are positionally fixed.  They are trapped in cells which are filled with rigid walls that are made of cellulose which prevents the movement of cells and tissues.  The plants form three basic tissue systems without gastrulation (1st layer – dermal, 2nd layer – ground and 3rd layer – vascular).
  16. 16. Rigidity of the body shape Animal Plants  Body plan is clearly determined in most parts  Highly regulated by the environment
  17. 17. Animal body plan is clearly determined in most parts.  In different life stages, they are mostly clearly determined by its genes.  If for example, they change their movement to another place or change their short and long term behaviour, the body plan may change.
  18. 18. Plant development is highly regulated by the environment.  They are in variation and characterized by multiple times occurs also in iterative structures.  The organ proportions and frequency may vary.
  19. 19. Multicellular stages Animals Plants  One continuously multicellular stage  They have haploid and diploid stages.
  20. 20. Animal life cycle is just one continuously multicellular stage  Many animals undergo one or more transformation, when their body plan changes dramatically.
  21. 21. Life cycle of all plants have haploid and diploid stages.  That life cycle is called alternation of generations.  They are leading to two different body plants during their life cycle (sporophyte and gametophyte)
  22. 22. Meiosis Animals Plants  Gametes are formed directly through meiosis.  They undergo no gametic meiosis, but a sporic meiosis.
  23. 23. Animal gametes are formed directly through meiosis.  There is nothing that could be compared to the gametophyte in plants.
  24. 24. Plants undergo no gametic meiosis, but a sporic meiosis.  The plants produces spores instead of gametes.  Gametophyte is first formed by mitotic divisions, then forms the gametes.
  25. 25. Germline Animals Plants  They set aside reproductive stem cells in early development.  No reproductive stem cells are set aside in the early development of plants.
  26. 26. Animal species set aside reproductory stem cells in early development.  This decreases the accumulation of mutation.
  27. 27. No reproductory stem cells are set aside early in development in plants.  Some plants live still certain meristems or meristem parts more inactive till the gametophyte is to be formed.
  28. 28. Morphogenesis Animals Plants  Distinct, complete body shape  Longer period of morphogenesis
  29. 29. Animals develop to a distinct, complete body shape.  Some reorganization may take place during the animal life stages.  In seldom cases, new structures will develop.  Other animals develop stepwise into different shapes.
  30. 30. Plants go through a longer period of morphogenesis.  Plants during their development do not head for a distinct body plan.  Many plants grow and develop on and on till they die.  Meristems which are areas of actively dividing undifferentiated cells allows for iterative growth and the formation of more and more new organs and structures during a plants life.  Resemblance of embryonic stem cells in animals is present yet continually existing during adult life stages.
  31. 31. Plasticity Animals Plants  They are determinated early in development.  Enormous plasticity in their development is present.
  32. 32. Animal cells are determined early in development  Animal cells developed into tissues but they are clearly determined, but in most cases, they are irreversibly determined.  Most tissues regenerates from stem cells, however, occurs at some animal species like Ambystoma mexicanum.
  33. 33. Plants show an enormous plasticity in their development.  Axillary meristems often grows out in order to substitute for the lost part.  Strategies resembles the regeneration of the limb in some animals.  Whole plants can be regenerated from single cells.  Form of a plant is strongly affected by environmental factors such as light and temperature, results in great variety of morphologies from the same genotype.
  34. 34. Plant forms affected by environmental conditions could be of: 1. Branching 2. Height 3. Relative Portions of Vegetative and Reproductive Structures
  35. 35.  That amazing level of plasticity helps plants compensate for their lack of mobility.