my $str = '
AAGTAATCAAGTATTACAAGAAACAAAAATTCAAGTAAATAACAGATAAT
ATGTCAAAAGCTGTCGGTATTGATTTAGGTACAACATACTCGTGTGTTGC
                                                  
>YDR256C  CTA1  969666  970216
GGGAAGAACTAAGAGATGTTATGGCTCGGAGAGTTTTGAAAAGCGAAATA
GATTCGCTGCAAGTTTGTGAAGAAACCATCGACAAGAATTACAAGGTTAT
';

# and it can be more than one empty lines