HL 1 Biology

4.4c Cloning & GMOs

AA-CC: 171-4

<<Human Genome Project (HGP)>>

  • HGP:  a co-operative venture between many different independent research groups as well as Celera Genomics (private research company)
  • HGP was able to: obtain a sequence of human genome (all the DNA in the human cell)
    • fewer protein-coding regions found in genome than expected
    • estimate of total # of human genes reduced from 100,000 to 25,000
  • “junk DNA”: sections of DNA that do not code for proteins
  • Bioinformatics: use of computers to store + analyse the large amounts of data being generated by the sequencing of genomes
  • Pharmacogenomics: a field which links differences in genomic information in differenet populations to any differences in their response to drug treatment.
  • HGP’s improvements in sequencing technology enabled to: study genomes of other organisms (e.g. mice) and study particular genetic disorder in humans by comparing to DNA sequence in mice.
  • comparing genomes will facilitate evolution studies

<<Cloning>>

  • Clone: a group of genetically identical organisms or a group of cells derived from a single parent cell
  • Can happen naturally
    • asexual reproduction produces genetically identical progeny
    • identical twins are genetically identical
    • in livestock: eggs can be fertilized in vitro + allowed to develop into a multicellular embryo while they are pluripotent (capable of developing into all types of tissue)
    • limited clones – embryo cells no longer pluripotent after certain divisions
  • By using non-reproductive cells
    • Dolly the sheep – first mammal cloned from adult cell
    • Cell taken from udder of donor adult + cultured for 6 d
    • unfertilized egg taken from another sheep, nucleus removed from egg
    • egg wihout nucleus  fused with donor cell using a spark of electricity
    • surrogate mother gives birth to lamb (thats genetically identical to dolly )

=========DBQ==================

Comparing Mouse and Human Genomes (p.171)

1) 20

2) X, 1, 14

3)  1,  13

4) Reasons for many similarities between the mouse and the human include a common history background which can explain the similar homologous genes. Also, through evolution the human and mouse should have inherited different traits to evolve around their environment.

5) Chromosomes have mutated during the evolution of animals such as mice and humans by fusion or even duplication of the chromosomes.

Determining an Open Reading Frame (p.172)

1)64

2) 3 out of 64

3) In an open reading frame, the frequency of the stop codon occurring is low. The third reading frame may be open  because there are no stop codons, which is different compared to the first and second reading frame  contain at least one stop codon. The third frame should have a longer sequence in order to examine the stop codons.

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