Straight from perldoc -f split

Splits the string EXPR into a list of strings and returns that
list.  By default, empty leading fields are preserved, and
empty trailing ones are deleted.
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The only exemption is the pattern split(' ',$str) so just add a grep

perl -MData::Dumper -e '
$str = "GTGNNTNNG"; 
@nseg = split(/[ATCG]+/,$str); 
@nseg = grep {/./} @nseg;
print Dumper \@nseg;'
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