Lecture Notes on CS262: Introduction to Computational Genomics, Lecture notes of Biology

Download Lecture Notes on CS262: Introduction to Computational Genomics and more Lecture notes Biology in PDF only on Docsity! CS  262—Lecture  1  Notes     • 4-­‐5  HWs,  3  late  days   • (Optional)  scribing:  Due  week  after  lecture;  Replace  2  lowest  problems  from   each  problem  set   • Optional  textbook:  Biological  Sequence  Analysis  by  Durbin   • Computational  genomics  started  taking  off  around  the  time  of  the  sequencing   of  the  Human  Genome  in  2000     • Central  Dogma  of  Molecular  Biology   o DNA  in  nucleus  of  eukaryotic  cells  encodes  genes  è  transcription   leads  to  RNA  in  cytoplasm  è  Translation  leads  to  proteins,  the   building  blocks  for  life   • Goal  for  21st  century:  Convert  biology  fro  descriptive  science  to  quantitative,   predictive  sciences   • Price  of  genome  drastically  dropping:  $30,000,000  in  2004  to  $1000  today     Intro  to  Biology   • DNA  in  nucleus  and  each  cell  has  copies  of  DNA   o Although  we  have  trillions  of  cells,  an  average  somatic  cell  only  has   30-­‐60  differences  from  the  “pure”,  original  genome   • DNA  packed  into  chromosomes;  DNA  wrapped  around  histones,  which  are   wrapped  around  nucleosomes,  which  form  chromosomes   o Multiple  levels  of  packing   • 4  nucleotide  bases:  Adenine  (A),  Guanine  (G),  Thymine  (T),  Cytosine  (C)   o A  binds  with  T  and  C  binds  with  G   o As  such,  DNA  is  double  stranded   • DNA  must  be  read  from  5’  to  3’  end   • RNA  usually  single-­‐stranded   o Uracil  replaces  Thymine  in  RNA   • Gene  transcription:  Transcription  factors  recognize  binding  sites  in  DNA,   recruits  RNA  polymerase   o RNA  polymerases  actually  transcribes  the  DNA  strand   o Presence  or  absence  of  transcription  factor  dictates  whether   transcription  occurs,  or  in  what  amounts   • DNA  à  transcription  to  RNA  à  splicing  out  of  introns  leads  to  mRNA  à   translation  leads  to  protein     • Proteins  composed  of  one  of  20  amino  acids   • Specified  start  codon  (AUG;  Methionine)  and  multiple  stop  codons   • A  non-­‐coding  RNA  called  tRNA  folds  into  itself  into  a  complex  3D-­‐structure.   It  has  an  anti-­‐codon  that  pairs  with  the  reverse  complement  codon  in  the   mRNA  and  releases  the  correct  amino  acid     • There  can  be  errors,  or  mutations,  in  the  translation  process