B6.2 Breeding and engineering Flashcards
What is selective breeding?
Taking the best plants or organisms and breeding them together to get better offspring
What are two drawbacks of selective breeding?
Reduces gene pool population
Inbreeding
Explain the drawback: Reduces gene pool population?
Selective breeding is selecting certain alleles that code for the traits we want, so bad alleles are discounted and it leads to a smaller pool of alleles available
What is a gene pool?
Collection of different alleles in a population
Explain the drawback: Inbreeding? (2)
The best individuals are often closely related and breeding together can make them prone to diseases or inherited disfects
There is also less variation within a population so pathogens can kill them all
How does genetic engineering work?
They will have a desirable characteristic they want.
Take the gene responsible for that trait and transfer it to an organism so it develops the same trait.
It modifies the organisms genome
What is gene therapy?
Giving a person the healthy version of a gene in the hope it will fix an inherited disorder
Why is gene therapy difficult?
The faulty gene is in every body cell so you would have to transfer the new gene into every cell in the body
What is the solution to the problem which occurs with gene therapy? ( faulty genes in every body cell)
Transfer gene at early stage of development so as they develop it gets passed into other cells
What are the PROs of genetically modified crops?
Easily give them desirable characteristics (eg. more food can be produced for less money)
What are the negatives of genetically modified crops?
We dont know for certain how they affect our health
How do you transfer the gene from one organism to another? (4 stages)
Find gene we want then isolate it from donor organism with enzymes.
Insert gene into vector ( virus or bacterial plasmid)
Introduce vector to the host organism
Organism will take vector and gene and then produce protein the gene codes for
What is an example of transferring the genes from one organism to another?
Bacteria to produce medical drugs like insulin
What is a restriction enzyme?
Cuts the donor DNA at a specific base
What is the ligase enzyme?
Rejoins DNA strands at sticky ends. Both host and donor DNA have same sticky ends
What is a sticky end?
A staggered cut leaving a few exposed unpaired bases
How can you check the gene transfer was successful?
Insert an antibiotic resistant gene into plasmid at same time as the gene characteristic . Transfer some of the bacteria and let it grow.
Any bacterial colonies present will contain the antibiotic resistance marker gene.
