my %snp;
for my $snpId ( ... ) {
    for my $geneId ( ... ) {
        for my $transcriptId ( ... ) {
            for my $propertyId ( ... ) {
                $snp{ $snpId }{ $geneId }{ $TranscriptId }{ $propertyId } = ...;
            }
        }
    }
}

##</code><code>##

my %snp;
for my $snpId ( ... ) {
    for my $geneId ( ... ) {
        for my $transcriptId ( ... ) {
            for my $propertyId ( ... ) {
                $snp{ join $;, $snpId, $geneId, $TranscriptId, $propertyId } = ...;
            }
        }
    }
}