First remove non-ACGTacgt, then split on acgt:

$s = 'G_I1E2_GTGGAG^303CTGgacgCCCTGC_I2E3_TACA';;

$s =~ tr[ACGTacgt][]cd;;

print for split '[acgt]+', $s;;
GGTGGAGCTG
CCCTGCTACA

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The start of some sanity?

In reply to Re: extract only uppercases from string by BrowserUk
in thread extract only uppercases from string by losher

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