Download 10 Worksheet 9 Handout for powerpoint Applying our Knowledg

__________________________
Genetic screening: to identify those with an increased risk of
inheriting a disorder
•
•
•
•
Often tied to ethnic background
May involve karyotyping or biochemical tests
Then treatment or counselling can be given
Huntington’s disease can be screened for (autosomal
dominant trait)
_____________________________
Risk groups:
• Pregnant women over 35
years old
• Parents with genetic
abnormality in previous
children
• Parents who have family
members with genetic
abnormalities
• Couple from high risk
backgrounds for a specific
disease
___________________________:
involves checking the fetus for a
problem
• One of the processes is called
amniocentesis
• during 16 week of pregnancy by
inserting needle
• Uses amniotic fluid, which
contains fetus cells
• An ultrasound can be used to
prevent injury to mother or fetus
•to visually identify physical
abnormalities
_________________________: is the result of foreign
DNA inserted into an organisms DNA
Dr. Barbara _____________________ (1902-1992)
Research focused on making the connection between the behaviour of
chromosomes in a special type of crossing over and the phenotypic
effects on corn kernals
•
1951 - “Jumping gene” theory, now known as transposons
•
Little attention was paid to her theories
•
Transposons have large role in gene
regulation and help explain wide
range of variation in certain
proteins (pigments)
•
Received a Nobel Prize
for her work in 1983 (over 30 years later)
____________________________:
direct use of genetic techniques to treat a genetic condition
Two methods:
1. Normal gene product can be given to an affected
individual
• Used extensively today, example is insulin.
2. Manipulate the abnormal DNA in parent or offspring in
order to better the disease
____________________:
Physical alteration of genes.
•Can be used to correct some hereditary defects
• Involve inserting a proper working gene into the cell that
lack the ability to produce their own protein
• Insulin, inserting that gene into pancreatic cells
• Need to use a vector to insert the gene, like a virus, which is site
specific to pancreatic cells
• Once there the virus would insert the genes, giving these cells
the ability to produce their own insulin
_____________________
• Transfer of technology to the private sector
• Interesting facts:
– 50% of HG is non-coding “junk” DNA
– 30 000 – 35 000 genes
– gene transfer from bacteria
– Mutations 50% more likely in
 vs 
– 50% of HG is similar (transposable elements)
– 3 164 700 million nucleotides
– Crossing over more frequent in short chromosomes
_________________
• Clones have identical
DNA to “parent”
• Dolly the Sheep
(1997) by Ian Wilmut
• First mammal cloned
from the nucleus of
another adult mammal
___________________
• A technology that has
replaced blood typing
for paternity or
criminal prosecutions
• Each person has a
unique DNA
“fingerprint” that can
be identified from a
small sample of DNA
Can you give possible points in support of or opposition to the
following statements?
A) “Prospective parents who have a family history of a genetic condition
that can be identified in prenatal testing and are at risk should be
required to undergo genetic screening.”
b) “Ultimately you would hope all parents would take advantage of
screening techniques in an effort to reduce the frequency of children
born with genetic abnormalities.”
c) “As long as there are strict guidelines controlling gene therapy, society
will not have to be concerned about abuses of this technology.”
d) “Private biotech companies that have invested millions of dollar in the
Human Genome Project have a right to obtain patents for specific
gene sequences. Other private companies or research facilities should
have to ask permission or even pay to use this information in their
studies.”
PRACTICE QUESTIONS
1. Why is it advantageous to control breeding in
plants and animals?
2. How is inbreeding performed in a) plants, b)
animals?
3. List the problems that can result from inbreeding.
4. Briefly outline three of the roles of genetics in
medicine.
5. What types of individuals are most likely to consult
with a genetic counsellor?
6. Briefly explain how amniocentesis is performed.