1 / 34

Chapters 47 & 21

Chapters 47 & 21. Animal Development & The Genetic Basis of Development. DEVELOPMENT. An organism arises from a fertilized egg as the result of three related processes Cell division Cell differentiation Morphogenesis.

lillian-buchanan
Download Presentation

Chapters 47 & 21

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapters 47 & 21 Animal Development & The Genetic Basis of Development

  2. DEVELOPMENT • An organism arises from a fertilized egg as the result of three related processes • Cell division • Cell differentiation • Morphogenesis

  3. How does the ball of cells know when and where to differentiate, fold etc.? Cytoplasmic Determinants !(usually maternal factors like mRNA, proteins, other chemicals) They are non-homogenous

  4. Early Morphogenesis: Gastrulation & Neurulation Neurulation video http://www.youtube.com/watch?v=ZeIyrInOnMc

  5. Fertilization • Gray crescent • Establishing the body axes • What is determination? • What is induction?

  6. REGULATION OF GENE EXPRESSION • Transcriptional regulation is directed by: TRANSCRIPTION FACTORSsuch as: • Maternal molecules in the cell’s cytoplasm (cytoplasmic determinants) • Signals from other cells (induction)

  7. Drosophila melanogaster • Each segment in the adult fly is anatomically distinct • And also has characteristic appendages… just like you? HEAD THORAX ABDOMEN

  8. Drosophila melanogaster • Maternal cytoplasmic determinants • GRADIENTS of chemicals are important • Segmentation genes • Gap genes • Pair rule genes • Segment polarity genes • http://www.youtube.com/watch?feature=endscreen&v=MefTPoeVQ3w&NR=1 • http://www.youtube.com/watch?v=uaedzlrnBGY • http://flymove.uni-muenster.de/Processes/Segmentation/SegPair/SegPairEst/SegPairEstGes.html

  9. HOMEOTIC GENES • Master regulatory genes • Specify the types of appendages and other structures that each segment will form • Mutations produce flies with structures in incorrect places

  10. Normal adult fly Antennapedia mutant Bithorax mutant Examples of Homeotic Mutations

  11. Wild-type Mutants Antennapedia Mutations

  12. HOMEOTIC GENES • are master genes that regulate the expression of numerous other genes • Some of the regulated genes are regulatory themselves

  13. Drosophila DEVELOPMENT REVIEW: Hierarchy of Gene Activity • Maternal genes in cytoplasm of the egg • Segmentation genes of embryo • Gap genes • Pair-rule genes • Segment polarity genes • Homeotic genes of the embryo • Other genes of the embryo

  14. HOMEOTIC GENES • all possess homologous segments • 180-nucleotide sequence = homeobox (HOX) • Which encodes 60-amino-acid homeodomain

  15. Homeodomain • Homeotic genes • encode for transcription factors that influence other developmental genes • all have a hox region (homeobox) • which folds into a protein called the homeodomain. • Homeodomain is the DNA Binding region of the transcription factor

  16. HOMEOTIC GENES • Vertebrate genes homologous to the homeotic genes of Drosophila have maintained their chromosomal arrangement

  17. Ultrabithorax • Other interesting gene names in Drosophila http://jpetrie.myweb.uga.edu/genes.html Regulatin’ Genes song for fun: http://www.youtube.com/watch?v=9k_oKK4Teco

More Related