Card Set Information
stem cells and cloning
Where do IPSCs derive from?
from non-pluripotent cell
When were IPSCs introduced to mouses ?
When were IPSCs introduced to humans?
How were IPSCs produced?
by transfection of cells with genesc coding for transcription factors
How many transcription factors were found to be sufficient to induce cells to become stem cells?
it only took 4 transcription factors to induce cells to stem cells
What was an intial problem when producing IPSCs?
genes for transcription factors were incorporated in retroviruses thus induced cell also had genes for the retroviruses
What was the solution for the intial problem when producing IPSCs?
that codes for these transcription factors
*therefore the induced cells do not have retroviruses
Problem with the new method of producing IPSCs?
at least one of the transcription factors is a cancer-promoter
*there was a chance that cells can grow out of control
What does cloning mean in GREEK?
twig or branch
What does clone a gene mean?
put a small stretch of DNA from one organism into the genome of another (usually a bacterial cell)
What does clone a cell mean?
make many copies of a bacterial cell
**clone an organism from one single cell
What was the result from cloning a sheep experiment?
the results support that mature cells contain all the genes in the genome it is jsut that some are turned off
How can one turn on or off different sections of genome?
by epigentic modulation
In epigenetic modificaiton, are we modifying the sequence of DNA nucleotides?
no we are just altering whether or not the gene can be expressed thats all
What causes cells to become pluripotent?
there is an unknown factor inside the eggs cytoplasm
What do homeotic genes trigger?
the development of structures that are appropriate to each type of segment
What does homeosis do?
example) it transplants a wing tissue elsewhere at this stage will produce wing tissue in the new location
***fly has legs in place of antenna
Why does homeosis occur?
it occurs when cells get incorrect information about where they are in the body
What do hox (homeotic genes) genes code for
regulatory transcription factors that trigger the production of segment specific structures
What is homeobox?
the site along the DNA where the transcription factors bind
-very similar between different organisms
Hox genes AND similarities between different organisms
the hox genes on a fly chromosome correlates with the expression in a mouse
key points for hox genes- hox genes AND relation between different organisms (2)
hox genes are very closely related in creatures as distinct as fruit flies and humans
-this implies that the genes are a million years old
What does the relation between different organisms and the similarities of their hox genes imply?
that there is an ancient origin of these genes
How can hox genes be changed a bit? and what can it lead to?
through alteration in transcription factors (enhancer or silencers). This binding can lead to the development of new forms
***key factor in evolution