Mar 22, 2011

The Valuable Antisense



The particular terminology with respect to Gene Expression is quite confusing for beginners. at least i have faced this problem during my student life.

the sense strand ( DNA)
the nonsense or antisense strand( DNA)

here antisense or nonsense strand is the active strand that participates in transcription.
whereas
the sense strand just opposite complimentary strand.


So according to this definition - The ANTI-SENSE is VALUABLE

But this makes things complicated. And it is further complicated by Using Additional terminology
coding and non- coding strand.
here again interestingly coding strand is actually not participating strand.
and it is non-coding strand that undergoes transcription.
So say anti- sense or non- coding, it points to same strand - that undergoes transcription.

what beginner in molecular biology may think that 
in DNA helix which consist of double strand, out of the these  two strands
 one strand is sense strand and the other is antisense strand.

But this is not true if we scrutinize this definition.
why?
Because-
1) in reality particular transcription occurs only in very short stretch of DNA strand with respect to full length of DNA. ( particular gene - from promoter region to terminator region)

2) since Genes are present on both the strands, same strand of DNA may become antisense for one gene and sense strand for another gene. see in fig. gene1 and gene2 carefully template strand in two genes are not the same.






So I prefer simple and unambiguous terminology and snuggest students to follow this and keep things simple.-template strand and non- template strand for a specific gene.

Template Strand- is that stretch of DNA which acts as template for transcription. (mind it, only stretch DNA from specific promoter to terminator not full length DNA)
and
Non- Template Strand- is just a H- bonded opposite complimentary stretch of the DNA strand.

So be sensible, do not heed much to nonsense things.




Mar 17, 2011

GENE



It is by convention,
when a DNA sequence associated with a gene is specified,
it is the sequence of the non-template strand that is given,
and it is written in the 5'-to-3' direction.

This convention is adopted
because the sequence of the non-template strand corresponds to the sequence of the RNA that is made. (except T is replaced by U)

Mar 15, 2011

DNA WORLD- a humble beginning.

God bestowed me opportunity to learn and then responsibility to spread the knowledge.
This is a humble beginning in the field of" life sciences". So , here i am starting with "DNA world". Its a simple communication with people who are in this field. My special interest would be students who are entering in this beautiful field of life sciences.
Let us hope for the best.
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