public String getSequence() {
        // Create UTR sequence
        StringBuffer sb = new StringBuffer();
        for (Utr5prime utr : get5primeUtrs()) {
            Exon ex = (Exon) utr.getParent();
            String utrSeq = ex.getSequence();
            if (utr.size() < utrSeq.length())
                utrSeq = utrSeq.substring(0, utr.size()); // UTR5' may stop before end of exon
            sb.append(utrSeq);
        }

        return sb.toString();
    }