dna

[xenogen]

any changes occur in DNA from origin to wright now

[theprof]

Assuming you're talking in terms of evolution, yes changes will always occur.

Look at it like this. DNA is a chemical and just like other chemicals it can be damaged (altered) by other chemicals, radiation and cosmic rays. Now whilst DNA can be repaired, the repairs sometimes do not allow the DNA to work as effectively as before. These chemical changes are DNA mutations and are unavoidable during evolution.

Furthermore, DNA replication is not 100% accurate and mistakes do occur during replication.

So all in all, there's a lot of it about in all species.