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Key Concepts•What are three ways of producing organisms with desired traits?•What is the goal of the Human Genome Project?
One of 3 methods used to develop organisms with desirable traits
Select organisms with desirable traits to be parents of next generation
Ex: Corn, dogs Two selective breeding
techniques are inbreeding and hybridization
Crossing 2 individuals that have similar characteristics Ex. Crossing 2 turkeys that are both plump and grow quickly- offspring
are likely to have both those desirable qualities
Inbred organisms have alleles that are very similar to parents
Inbred organisms are genetically very similar so they may inherit alleles that lead to genetic disorders
Breeders cross 2 genetically different individuals
Hybrid that results is bred to have best traits from both parents
Ex. Crossing one type of corn with large kernels with another that is resistant to disease. Result might be hybrid corn with both of the desired traits
Clone – an organism that has exactly the same genes as the organism from which it was produced
Easy to clone many plants – cut a stem, put it in soil and water, and it will develop into a new plant – genetically the same as the parent
Researchers have been cloning animals such as sheep, cows, goats and pigs
Click and Clone
Genes from one organism are transferred into the DNA of another organism
Used to produce medicines and improve food crops
Used to produce insulin Bacteria has 1 DNA molecule in the cytoplasm Also has small circular pieces of DNA called
plasmids Scientists insert a human gene into the plasmid The bacteria and all its offspring will now make
the protein that this gene codes for –in this case insulin
Since bacteria reproduce very quickly, large amounts of insulin can be produced
Can use technique to insert genes into other animals
Human genes can be inserted into the cells of cows – The cows will produce the protein for which the gene codes in their milk
This has been used to produce the blood clotting protein needed by people with hemophilia
Genes have also been inserted into plants to help them survive in cold temperatures and resist insect pests
Using genetic engineering to correct genetic disorders
Involves inserting copies of a gene directly into a person’s cells
Ex. To treat hemophilia, doctors would replace the defective allele on the X chromosome so the person’s blood would clot normally
First, scientists must find the best way to correct the genetic defect that is causing the disorder Correct or increase the defective cell product Make diseased cells weaker Block operation of diseased cells
Second – scientists must find a way to carry the genetically engineered DNA to target cells Viruses are an excellent candidate to deliver the
genes because they infect living cells Virus must be genetically engineered to render it
harmless
Some people are concerned about long-term effects of genetic engineering
Ex. Are genetically modified foods safe? Concerns that they may harm the environment or
cause health problems in humans
Scientists are trying to address these concerns and learn more about the effects of genetic engineering
The Human Genome Project
Genome – all the DNA in one cell of an organism
Main goal of Human Genome Project has been to identify the DNA sequence of every gene in the human genome
Completed first draft - found that we have at least 30,000 genes. Average gene has 3,000 bases
DNA technology can be used to identify people and show relationships DNA is broken down into small
fragments. Selected fragments are used to produce a pattern similar to a fingerprint
Except for identical twins no 2 people have the same DNA fingerprint