What is non-coding DNA?
Q: What is non-coding DNA?
A: Non-coding DNA are parts of an organism's DNA which do not code for protein sequences.
Q: What is the amount of non-coding DNA in different species?
A: The amount of non-coding DNA varies greatly between species. For example, over 98% of the human genome is noncoding DNA, while only about 2% of a typical bacterial genome is non-coding DNA.
Q: What was initially thought to be the purpose of non-coding DNA?
A: At first, much non-coding DNA had no known biological function and it was called junk DNA, particularly in the press.
Q: Are there any functions associated with some types of non-codingDNA?
A: Yes, many non-coding sequences are functional. These include genes for functional RNA molecules and other sequences such as "start replication" signals, centromeres, and telomeres.
Q: Is it possible that some types of non- codingDNA have yet to be discovered functions?
A: Yes, other noncoding sequences have not yet been discovered functions which can be inferred from the high levels of sequence similarity seen in different species' DNAs.
Q: What did ENCODE project suggest about the percentage of useful/functionalnon codingDNA in humans?
A: The Encyclopedia of DNA Elements (ENCODE) project suggested in September 2012 that over 80%of DNAs in human genome "serves some purpose".
Q: Was this conclusion accepted by all scientists or were there criticisms against this suggestion?
A: This conclusion was strongly criticized by some other scientists.
