Guruprasad,
There are two issues with your reply - Your mail client is sending the
reply to a thread as a separate mail instead of as a part of the
original thread (maybe because it uses 'RE:' to mark replies instead
of the usual 'Re:' but I am not sure about it).
The other thing is you're not properly quoting the email before
replying to it, when you quote 2 lines, actually the quote symbol is
present only in the first line which will wrongly imply that you typed
the second line as a part of the reply. I request you to consider
fixing these issues before replying to emails. :)