使用perl在多个蛋白质序列中找到Palindromes（完美的回文）

I am a newbie in Perl (Regular Expressions). I need aa example on how to write a program for finding out palindromes (perfect) in more than one protein sequences (let it be 4 sequence with 200 amino acids in number, in a file) I have to filter out, the palindromes and the position of palindromes present in the sequences.I am a newbie in Perl (Regular Expressions). I