Prep for USMLEPrep for USMLE
         Forum      |     Resources New Posts   |   Register   |   Login





 genetics  



Post Reply  
  • 0/5
  • 1
  • 2
  • 3
  • 4
  • 5


Tags:    
Author10 Posts
  #1

Give examples for each:

1. transition
2.transversion
3.missence mutation
4.frameshift mutation
5.large segment deletion
6. splice donor mutation
7. triplet repeat expansion




  #2

[quote="asmi"]Give examples for each:

1. transition - Purine for a purine (G for A), Pyrimidine for pyrimidine (C for U)

2.transversion - Purine for pyrimidine & vice versa

3.missence mutation - Valine for Glutamate in HbS

4.frameshift mutation- Duchennes dystrophy

5.large segment deletion - Alpha Thalassemia, Criduchat

6. splice donor mutation - Tay Sachs, Beta Thalassemia, Gauchers

7. triplet repeat expansion - fragile X(CGG),Huntington(CAG),Myotonic and spinobulbar dystrophies
:wink:


  #3

thnx..

and example of drugs causing transitions....5 -FU
for tansversion......alkylating agents


myotonic dystrophy shows CTG repeats.


  #4

MY GENETICS IS NOT GOOD , I HAVE TO ADMIT THAT.MY QUESTION IS NOW ABOUT FRAME SHIFT . DO WE SEE FRAME SHIFT MUTATION OF PURINE AND PYRIMIDINE BASES.OR FRAME SHIFT MUTATION IS COMPLETELY DIFFERENT CONCEPT.
I WAY APPRECIATE IF SOME ONE CAN HELP ME UNDERSTAND GENETICS IN SHORT TIME OR ANYSNY SUGGESTION HOW TO GET READY FOR IT WITH OUT HAVING ANXIETY ATTACK.


  #5

www.geneclinics.org/servlet...=8888890&key=RuZ16SA4hiRYz


  #6

frameshift mutation: (synonyms: out-of-frame deletion, out-of-frame mutation) An insertion or deletion involving a number of base pairs that is not a multiple of three and consequently disrupts the triplet reading frame, usually leading to the creation of a premature termination (stop) codon and resulting in a truncated protein product


  #7

"peekay" wrote:
MY GENETICS IS NOT GOOD , I HAVE TO ADMIT THAT.MY QUESTION IS NOW ABOUT FRAME SHIFT . DO WE SEE FRAME SHIFT MUTATION OF PURINE AND PYRIMIDINE BASES.OR FRAME SHIFT MUTATION IS COMPLETELY DIFFERENT CONCEPT.
I WAY APPRECIATE IF SOME ONE CAN HELP ME UNDERSTAND GENETICS IN SHORT TIME OR ANYSNY SUGGESTION HOW TO GET READY FOR IT WITH OUT HAVING ANXIETY ATTACK.


FRAMESHIFT MUTATION: simply means that amino acids (not in multiples of 3 ), were deleted causing misreading.
ex: CTG CAA GTC CTG
if 2 consecutive amino acids CA were removed, it will become:
CTG AGT CCT G
notice that the 2nd codon originally CAA became AGT.hence this is a Frameshift mutation.example of this is Duchenne's Dystropy. (severe type of muscle dystrophy)

it would be adifferent story if mutiples of 3 were deleted, using the same example; if entire codon CAA were deleted, it wil be read as
CTG GTC CTG
notice that its still thesame codons as the original but with the 2nd original codon deleted.Ths is an In FRAME mutaion.(ex: Becker's dystrophy-which is a milder form of dystrophy.)

I hope i was able to answer ur q.
Yeah, i know how u feel.Genetics is really intimidating.
But we really have to deal with it.God bless us :lol:


  #8

that was a nice explanation ..

keep it up :idea:


  #9

THHANK YOU GUYS. I WILL UNDERSTAND THAT EXAMPLE AND CHECK THAT SITE AS WELL.


  #10

good list of eg..thanks step1taker





Bookmark and Share



This thread is closed, so you cannot post a reply.



Login or Register to post messages








show Similar forum topics

Genetics, genetics, to be or not to be!
Genetics Non-profit Organization
Genetics
show Related resources

Biochemistry & Genetics: PreTest Self-Assessment & Review
Medical Genetics
Elsevier's Integrated Genetics








Advertise | Support | Premium | Contact