Biotechnology- the use or alteration of cells or biological molecules for specific applications
Chp. 18- Genetically Modified Organisms
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Intro.
a. Recombinant DNA Technology-Adding foreign genes to bacteria or other single cells
i. When they reproduce they make several copies of the foreign DNA
ii. Fig. 18.3
b. Transgenic- animal with a genetic change in each of its cells
c. Gene Targeting- Adds or deletes specific genes of interest
Recombinant DNA Technology
a. Making Recomb. DNA Tech requirements
i. Restriction Enzymes- cut donor and recipient DNA
ii. Cloning Vectors- DNA to carry the donor DNA
1. Use Plasmids- circle of double stranded DNA naturally occurring (fig. 18.5&8)
iii. recipient cells – insert donor DNA
iv. Select cells that harbor DNA
v. Select recombinant cells that contain genes of interest
1. Create a Genomic Library- bacteria that harbor pieces of genome (HUGE)
a. Like searching GOOGLE
2. cDNA Library- (complimentary DNA) smaller b/c only protein encoding genes
a. Like searching a scientifically based webpage
vi. stimulate expression of the foreign gene – collect and purify protein product
b. Allows us to look at the functions of genes from complex organisms at the molecular level
Transgenic Organisms - Video
a. Plants - insert plasmid into protoplasts- cells with cell wall removed
b. Animals – DNA is inserted into cells using:
i. Liposomes- fatty bubbles that integrate into cell membrane
ii. Electroporation- electricity makes small holes in cell membrane
iii. Microinjection-microscopic needle
iv. Particle bombardment- shoot tiny medal particles into cell with foreign DNA on them
v. Viruses, Retroviruses, and chemicals
c. Pharming- inserting genes into hosts in order to produce desired proteins and harvesting them
d. transgenic technology can disrupt normal gene function
Gene Targeting
a. Homologous recombination- DNA locates similar or identical sequence and displaces it
b. “Knocking Out” – stops the function of a gene that the foreign DNA replaced
c. “Knockin” – genes that have an altered function are swapped in
Chp. 19- Gene Therapy and Genetic Counseling
Gene Therapy- replacing a malfunctioning gene to alleviate symptoms by delivering DNA
Genetic Counseling- calculating the risk of recurrence of inherited disorders in families, using pedigree charts
and applying the laws of inheritance
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Gene Therapy Successes and Setbacks- gene therapy doesn’t always work
The Mechanics of Gene Therapy
a. ex vivo gene therapy – cells are altered outside the body and then infused into the person
b. in situ gene therapy – the healthy gene plus the DNA that delivers it is injected directly into a
localized and accessible body part. (More invasive – more risk)
c. in vivo gene therapy- the vector is introduced directly into the body (most invasive)
d. Protein based therapies treat the phenotype by replacing a missing protein
e. Germline gene therapy- alters the DNA of a gamete or fertilized ovum. All resulting cells
changed (not being done in humans) – heritable
f. Somatic Gene therapy- Correct only the somatic cells that an illness affects – not heritable 19.4
g. Chimeraplasty- abnormal genes are not replaced, they are repaired by inserting DNA and RNA
Genetic Screening And Genetic Counseling
Chp. 21- Reproductive Technologies
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Infertility and Subfertility – Table 21.1
a. Male infertility often a deletion of part of the Y chromosome
b. Female infertility has many ties to genes (Hormones, structures, pH…)
c. Many fertility problems solved using in vitro fertilization – “fertilization in glass” (video)
Assisted Reproductive Technologies – Table 21.2
a. Preimplantation Genetic Diagnosis (PGD)- detects genetic and chromosomal abnormalities
before pregnancy starts
i. remove a cell from the 8 celled embryo leaving 7 which can be successful
ii. VERY controversial (sex selection…)
b. Polar body biopsy – genetic test on polar body to infer the genotype of the attached oocyte
i. analyze the polar body for mutant alleles
ii. if it has mutant than you know the oocyte does not have the mutant
Chp. 22- The Human Genome Project and Genomics
Genome Sequencing: A continuation of Genetics
a. Uses – Fig 22.1
b. Genetic maps have increased in level of detail – Fig 22.2
c. Positional Cloning- how does phenotype correspond to causative gene
i. in contrast to genome pjct. approach which was “sequence now, interpret later”
The Origin of the Idea
a. Francis Crick – E. coli, “What is true for E. coli is true for the elephant.”
b. Sanger – method of cutting and labeling DNA - Fig. 22.4
c. officially began pjct. in 1990
Technology Drives the Sequencing Effort for Genome pjct.
a. DNA sequencing and computer software to align DNA pieces were essential – Fig. 22.6
b. Expressed Sequence Tags- short pieces of cDNAs used to locate & tag protein encoding genes
c. DNA Microarrays- DNA embedded on glass
Genome Information Answers and Raises Questions
a. What is a gene?
b. Minimum # of genes required for life (265-350) – Tbl. 22.2
c. Genome Information will affect you in some way in the future