1. Mutations & Genetic Recombination

2. Mutation Permanent change in the genetic material of an organism
All mutations in gametes are inheritable because they are copied during DNA replication

3. Somatic cell mutations occur in body cells
Germ cell mutations occur in reproductive cells
These are passed on from one generation to the next

4. Types of mutations Point mutations
Chemical change that affects just one or a few nucleotides
May involve substitution of one nucleotide for another
Or the insertion or deletion of one or more nucleotides

5. Point mutations Minor effect on cell
Change in coding sequence does not always result in a different polypeptide
Ex. GGA  GGG both code for the amino acid, glycine

6. This is called a silent mutation Example: UAU and UAC
Even if the aa is substituted for another, it may not have a significant function in the final structure
This is called a silent mutation
Example: UAU and UAC
Mis-sense mutation
Results in an altered protein
Ex sickle cell disease is a point mutation that is very harmful

7. Nonsense mutation
Deletes a start signal or results in a premature stop signal
A nucleotide substitution that affects the regulatory sequence may result in a cell being unable to produce a functional protein

8. Frameshift
When an insertion or a deletion the codon reading frame is shifted and each codon is read incorrectly.
AAU GGU GCC
AAU GGUG GCC

9. Chromosomal Mutations
Crossing over
Loss or duplication of portions of DNA during DNA replication
Change to structural or regulatory DNA sequences

10. Causes of mutations Spontaneous mutations Induced
Caused by naturally occurring molecular interactions
Ex. Incorrect base pairing
Induced
Caused by agents outside the cell
Mutagens increase the rate of mutation

11. Physical Mutagens Cause physical changes to the structure of DNA
Ex. X-rays and gamma rays are the most damaging form of mutagen known
Also UV rays cause chemical reactions to form between adjacent A and T bases, interfering with replication
A single sunburn doubles the chance of getting skin cancer (melanoma)

12. Chemical Mutagens
A molecule that can enter the nucleus of the cell and induce mutations by reacting chemically with DNA
Can insert themselves and cause substitution or a frameshift mutation
Ex. Nitrates (a food preservative), gasoline fumes, 50 different compounds of cigarette smoke.

13. Carcinogenic
Chemical mutagens associated with one or more forms of cancer
Cancer is uncontrolled cell division
The result of somatic cells that disrupt the expression of genes involved in regulation of the cell cycle

14. Mutations and Genetic Variation
Single mutation has little or no effect on an organism
However, a series of mutations developed over time can be more serious.
Mutations accumulate within a cell
Different mutations over time help shed light on genetic variation

15. Tracing ancestry through mitochondrial DNA
Mitochondria and chloroplasts have there own DNA (which replicates, transcribes, and translates separately from nucleic DNA.
Evidence suggests that these organelles were once independent prokaryotic cells
Endosymbiont theory proposes that eukaryotes arose when one prokaryote was engulfed by another

16. Mitochodrial DNA (mtDNA)
Recall, the cytoplasm of the fertilized egg (zygote) is donated by the ovum.
All of your mtDNA is identical to your mothers
Mutations in mtDNA provide information about the evolutionary path of animals and plant species

17. The process of creating recombinant DNA involves 2 types of enzymes:
Restriction Enzymes – (DNA scissors) cut the DNA strand at specific sites -palindromes- and often creates sticky ends

18. 2. The now unpaired segments can be paired with complimentary nucleotides from a different strand of DNA
3. DNA ligase – is genetic glue that puts DNA strands back together.
rDNA

20. Application
Insulin used to be harvested from pigs, but some individuals did not tolerate it.
we are now able to use bacteria to produce human insulin in large quantities.
is tolerated much better by patients.
This procedure was first marketed in Canada in 1983!

22. Other Aspects of Biotechnology
Gene sequencing –determining the specific location and composition of specific genes.
The Human Genome Project : mapped our genes (3 billion nucleotides)
NOVA Online | Cracking the Code of Life | Sequence for Yourself

24. RFLP – restriction fragment length polymorphism –cut DNA into pieces
Gel Electrophoresis – separate the DNA pieces by size.

25. DNA fingerprinting
identify an individual based on their unique genetic code.
homologous segments of DNA are similar but contain unique patterns of nitrogen bases
identify individuals involved in crimes, paternity

26. DNA Fingerprinting

27. Misc. Technology
Polymerase chain reaction –making billions of copies of a piece of DNA- PCR Animation
Paternity Testing - Paternity Testing
Gene Gun - Genegun1

29. Recombinant DNA Genetic engineering
Manipulating genetic material to alter genes and blend plant, animal, and bacteria DNA together.
DNA that includes outside source is called recombinant DNA.
Rapidly growing field
Eg peppers

30. Restriction Endonucleases
Restriction enzymes cut DNA at specific nucleotide sequences
Restriction endonucleases cuts within the interior of a DNA molecule (rather than at ends)
It recognizes a target sequence (short sequence of nucleotides) and cuts within it at the restriction site.

31. Specificity: cuts are specific and predictable
Two characteristics
Specificity: cuts are specific and predictable
Meaning the same enzyme will cut the same target sequences producing the same set of DNA fragments called restriction fragments

32. Staggered cuts:
leave a few unpaired nucleotides on a single strand at each restriction fragment called sticky ends.
Sticky ends can pair with a complementary sticky end cut by he same restriction endonuclease from a different strand of DNA
DNA ligase Spliced the paired sticky ends together resulting in a stable recombinant DNA molecule.

33. animation