Evolutionary developmental biology


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Evolutionary developmental biology

  1. 1. Evolutionary Developmental Biology By: Julia Burton
  2. 2. Overview <ul><li>Evolutionary Developmental Biology </li></ul><ul><ul><li>Compares the development of different organisms in an attempt to understand ancestral relationships between organisms and the developmental mechanisms that bring about evolutionary change </li></ul></ul><ul><li>Also known as: Evo-Devo </li></ul><ul><li>Fairly new field of Biology </li></ul>
  3. 3. Overview, cont. <ul><li>Consists of the exploration of genes that control development in organisms </li></ul><ul><li>How it came to be </li></ul><ul><ul><li>Researchers became more interested in the similarities and differences between closely and distantly related species </li></ul></ul>
  4. 4. Developmental Genes <ul><li>Dev. Genes are very important to the phenotype of an organism </li></ul><ul><ul><li>Key players in the evolution of many traits </li></ul></ul><ul><ul><ul><li>Changes in genes affect traits that can be acted on by natural selection </li></ul></ul></ul><ul><ul><ul><li>Variation in the expression of those genes may be commonly involved in acquiring new traits </li></ul></ul></ul>
  5. 5. Developmental Genes, cont. <ul><li>Pattern formation: </li></ul><ul><ul><li>The process that gives rise to plants and animals with a particular structure </li></ul></ul><ul><ul><ul><li>Developmental genes control this and carry out tasks such as </li></ul></ul></ul><ul><ul><ul><ul><li>Cell division </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cell migration </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cell differentiation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cell death </li></ul></ul></ul></ul>
  6. 6. REAL LIFE Chicken Foot vs. Duck Foot <ul><li>Morphological differences between webbed and not webbed feet are due to different expressions of two cell-signaling proteins </li></ul><ul><ul><li>BMP4 </li></ul></ul><ul><ul><li>Gremlin (Drm) </li></ul></ul>
  7. 7. REAL LIFE Chicken Foot vs. Duck Foot, cont. <ul><li>BMP4 </li></ul><ul><ul><li>Expressed throughout the developing limb </li></ul></ul><ul><ul><li>Causes the cells to undergo apoptosis </li></ul></ul><ul><li>Gremlin </li></ul><ul><ul><li>Inhibits BMP4 from working </li></ul></ul><ul><ul><li>Allows cells to survive </li></ul></ul>
  8. 8. REAL LIFE Chicken Foot vs. Duck Foot, cont. <ul><li>In the Chicken </li></ul><ul><ul><li>Gremlin is expressed throughout the limb except in between each digit </li></ul></ul><ul><ul><li>Not webbed! </li></ul></ul><ul><li>In the Duck </li></ul><ul><ul><li>Gremlin is expressed everywhere </li></ul></ul><ul><ul><ul><li>Webbed! </li></ul></ul></ul>
  9. 9. REAL LIFE Chicken Foot vs. Duck Foot, cont. <ul><li>What scientists have done </li></ul><ul><ul><li>Tried inserting gremlin protein into the interdigit regions of the chicken and it was born with webbed feet! </li></ul></ul>
  10. 10. Hox Genes Important to Evolution <ul><li>Hox Genes </li></ul><ul><ul><li>In animals, a class of genes involved in pattern formation in early embryos </li></ul></ul><ul><ul><li>Short for homeobox containing genes </li></ul></ul><ul><li>They have been important in observing trends among large groups of species </li></ul><ul><li>Found in all animals </li></ul><ul><ul><li>Shows that they originated very early on in animal evolution </li></ul></ul>
  11. 11. Hox Genes Important to Evolution <ul><li>Scientists believe a variation in Hox genes may have started the formation of many new body plans </li></ul><ul><li>Number of Hox genes varies per animal </li></ul><ul><li>Multiple Hox genes occur in clusters </li></ul><ul><ul><li>Close together on the chromosome </li></ul></ul><ul><ul><li>Mammals: Hox genes have duplicated twice so far to create 4 clusters, all somewhat different. There are 38 genes in total </li></ul></ul><ul><li>The more Hox genes, the more complex the organism is! </li></ul>
  12. 12. Developmental Genes Affecting Growth Rate and Influencing Morphology <ul><li>Controlling relative growth rates of different parts of the body during development will cause genetic variation </li></ul><ul><li>Heterochrony </li></ul><ul><ul><li>Evolutionary changes in the rate or timing of developmental events </li></ul></ul>
  13. 13. Developmental Genes Affecting Growth Rates and Influencing Morphology <ul><li>Heterochrony can cause two things </li></ul><ul><ul><li>Different species with morphological changes </li></ul></ul><ul><ul><ul><li>(ex) human and chimpanzee skull </li></ul></ul></ul><ul><ul><ul><ul><li>Different parts grow at different rates </li></ul></ul></ul></ul><ul><ul><li>Affect development stage at which a species reproduces </li></ul></ul><ul><ul><ul><li>Parts of the body associated with reproduction develop faster than rest of the body </li></ul></ul></ul><ul><ul><ul><li>Reproduction may occur at the same known age, but non reproductive parts pay develop slower </li></ul></ul></ul><ul><ul><ul><li>Both will cause paedomorphosis … </li></ul></ul></ul>
  14. 14. REAL LIFE “Fountain of Youth” <ul><li>Brooke Greenberg </li></ul><ul><ul><li>Background Information </li></ul></ul><ul><ul><ul><li>Born January 8, 1993 </li></ul></ul></ul><ul><ul><ul><li>18 years old </li></ul></ul></ul><ul><ul><ul><li>Lives in Baltimore, Maryland </li></ul></ul></ul><ul><ul><ul><li>This is her today: </li></ul></ul></ul><ul><ul><ul><li>Why? </li></ul></ul></ul><ul><ul><ul><ul><li>She’s paedomorphic </li></ul></ul></ul></ul>
  15. 15. REAL LIFE “Fountain of Youth” <ul><li>Paedomorphosis </li></ul><ul><ul><li>The retention of juvenile traits in an adult organism </li></ul></ul><ul><li>Brooke suffers from what doctors call “Syndrome X” </li></ul><ul><ul><li>She has the mental capacity of a 9 month old and looks like a 13 month old </li></ul></ul><ul><li>Scientists are searching for gene mutations or any abnormalities in her DNA to see what is causing her not to age </li></ul>